How Long Does Old Paint Last? What To Do With Leftover Paint: Improovy (2024)

Whether you’ve found unopened cans in your basem*nt from previous owners or have paint cans past their lifespan in your crawlspace, our painting experts will help teach you how long does paint last.

Everyone has old paint cans lying around. But does paint go bad? Furthermore, how long does old paint last? Like many homeowners, you may be wondering if you can reuse leftover paint for touch-ups or in your next DIY paint job.

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The goal of this article is to answer how long paint lasts as well as proper disposal questions. In addition, we’ll show you how to make leftover paint last. This comprehensive home improvement old paint guide will help you make the best decision for your home, your family, and the environment.

Let’s start by answering the age-old question, does paint go bad?

Does Paint Go Bad?

Yes, all types of paint go bad eventually. A previously opened can of paint lasts 5 years on average if properly sealed and stored. Old paint shelf life can also vary among different types of paint.

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In particular, an unopened can of latex or acrylic paint lasts up to 10 years. For unopened paints that are oil-based or alkyd-based, the shelf life could be up to 15 years. Additionally, chalk paint has a shorter lifespan from 1-3 years, and milk paint only lasts 1-2 weeks after its mixed.

But how long paint lasts depends on the kind of paint being stored and the storage conditions. Unsealed paint stored in a garage with freezing temperatures will not last much past 1-2 years.

Damage from extreme temperatures affects all paint types in the same way. This includes paints and primers from Sherwin-Williams, Dulux, Glidden, Kilz, Zinnser, Benjamin Moore, or Behr.

Don’t worry, we will cover how to safely store paint and proper disposal methods in the section after next.

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How Do You Know if Paint is Bad?

You can tell paint has gone bad by the smell and texture. A rancid or sour-smelling paint means your paint has gone bad. In particular, the smell of bad paint is similar to sour milk.

Other indicators of expired paint include a lumpy or chunky paint consistency. For one, the expired paint will have adhesion issues. More importantly, it can be hazardous by giving off excess VOCs or paint fumes. In this case, it’s best to get new paint.

However, the paint may still be good if the water has separated from the solids. Over time, gravity pushes the solids to the bottom of a can. Despite this, the chemical makeup of the paint is the same.

In this instance, be sure to thoroughly shake or stir after opening the paint before you use it for any painting projects. This is shown in the photo above. After a good mixing using a paint stir stick, the exterior paint in the picture was still good.

Keep in mind that this is not the case if the paint has been frozen at any point. Upon a deep freeze, the solids and water will have separated permanently. If this is the case, you’ll want to buy new paint instead and properly dispose of the leftover cans.

Accordingly, a few keys to properly store paint include:

1. An airtight seal or fully closed lid on a paint can
2. Storage in a temperature-controlled room
3. Kept in a dry place without mildew or direct sunlight
4. Placed on a shelf, away from the reach of children

Mixing Old Paint

As a rule of thumb, you should always mix any old paint thoroughly prior. Even matching paint colors will look “off” color-wise when you apply it if not mixed well. Another best practice is to strain the paint. Straining removes the thin film or skin that forms on top of drying latex paints.

Without compromise, any mold or mildew inside the can is a huge red flag. This means it’s time to dispose of the old paint. One final indicator of if it’s time to toss the paint is a broken seal or if a lid was not secured properly on a can.

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How to Properly Dispose of Old Paints

If you find paint that has gone bad, do not use it to paint your walls or drywall touchups. Instead, you should properly dispose of the paint at home. Alternatively, you can drop off expired paint at a designated disposal facility if your city or county has one.

Oil-Based Paint Disposal

Proper disposal of oil-based paint is a giant hassle, which is why most new paints found at Benjamin Moore, Sherwin-Williams, or even Home Depot are water-based. In case you find leftover oil or alkyd-based paint, there is one very important thing to consider.

It is actually illegal in most states to throw away oil-based paints in the trash. Due to the solvents in oil-based or alkyd paints, they are considered hazardous waste and can contaminate soil and water.

Given that states like California prohibit tossing any old paint in your garbage, its best to check local paint recycling regulations. Luckily, many regions have designated paint drop off facilities. Not to mention, improper paint disposal is terrible for the environment whether it’s in a landfill or not. Moreover, never pour a substantial amount of old paint down a drain or toilet.

Lastly, some paint stores like Sherwin-Williams or Ace Hardware may still have a paint recycling program. Most have phased out paint drop-off services so make sure to call ahead.

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Latex Paints Disposal

Most new, modern paint formulations are acrylic latex or water-based. In addition to having lower VOCs compared to oil-based paints, acrylic paints are better for the environment. Not to mention, latex paint is much easier to store and dispose of properly. Courtesy of Chicago’s public health department, here are a few options to properly dispose of old latex or water-based paint at home:

1. If the paint is still good, donate it or use it by adding another coat of paint to a wall or by brushing or rolling some cardboard Amazon delivery boxes.
2. Dry up the old paint by leaving it out. Now if there is a lot of old paint, you can add kitty litter or shredded paper to soak up and absorb it. Once dry, you can toss it out as normal.

In order to avoid costly headaches, let’s go into more detail on how to store paint so it doesn’t go bad in the first place.

Storing Paint So It Doesn’t Go Bad

It’s best to store paint in a cooler, dry area that doesn’t experience extreme heat or freezing conditions. Depending on the type of paint, extreme temperature swings can damage the paint. Not to mention, it can potentially create a hazard in your house. That’s why you should keep the unused paint in a room that stays between 60-80 degrees.

Next, make sure the paint is properly sealed. When it comes to closing single-gallon cans, wipe excess paint from the lip first. Then use a rubber mallet to secure the lid, tapping the outer edges to avoid denting the middle. Additionally, you can household plastic wrap as a gasket between the lid and can of paint for a better, air-tight seal.

Another good idea is to store the paint on a shelf or somewhere where kids can’t reach it. What’s more, placing the paint higher up on a shelf also prevents the likelihood of mildew or mold buildup.

Lastly, keep the paint out of direct sunlight and avoid excess heat from a boiler or air vent. Indeed, heat fast forwards paint expiration dates. This is even more important with any oil-based paint or elastomeric stucco products. Notwithstanding, solvent-based paints can actually catch fire under extreme heat conditions.

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Leftover Paint Tips

There are a few remaining tips when it comes to storing different types of leftover paint. In this case, we will focus on the differences between interior paint versus exterior paint.

The key to both interior and exterior paint is to properly budget exactly how much paint you’ll need for your job in the first place. Paint companies like Sherwin-Williams and even hardware stores like Home Depot and Lowes all have paint buying calculator tools on their websites. For example, here is the paint buying calculator from Lowes.

Interior Paint

One professional tip to storing interior paint is to label each can properly. What I’d recommend is taking a permanent marker and writing the room, surface, and paint color on the top of the can. You can also include the paint sheen and painting finish or brand in case the label on the can is covered with paint.

Here are a few examples of what that would look like:

• Living Room – Walls – Warm Pewter in Eggshell – Benjamin Moore
• Master Bedroom – Ceilings – Flat Ceiling White By Glidden
• Guest Bathroom – Trim – Cornforth White (Farrow and Ball)

Accordingly, you should seal interior paints shortly after use and properly store them in a cool, dry room. Similar to the extra paint storage tips outlined earlier in the article.

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Exterior Paint

Because exterior paint is used outdoors, many homeowners mistakenly think it’s more resilient to temperature changes when stored away. This is actually not true. As a result, you should store exterior paints the same way you would interior paints. Exterior paints should be stored in a cool, dry area that maintains a temperature between 60-80 degrees.

For exterior paints, you should also label the can’s painting surface, color name, and sheen. Here are a few examples of labels given to exterior paints prior to storage:

• Siding – Navajo White – Satin (Sherwin Williams)
• Trim, Soffits – Dove White – Gloss (Benjamin Moore)
• Windows, Doors – Rushing Stream – Semigloss Enamel (Behr)

Furthermore, for cedar exteriors like the homes we paint in Naperville, you’ll likely be using a solid stain. Solid stains are stored the same way that exterior paints are stored.

As a last note for the painting contractors reading this. Being a painting company, we typically keep excess paint in a temperature-controlled storage unit. If possible, we’ll also donate it to our local salvation army or ask neighbors if they could use it. We also communicate how important it is to not overbuy paint to customers.

According to the EPA, an estimated 10 percent of paint purchased in the United States is left unused. Certainly, excess paint leads to improper disposal which can hurt the environment. Green initiatives like this and correctly budgeting how much paint you’ll need are essential to keeping customers and the planet happy.