If it smells unpleasant or you see mold, you will need to discard it (correctly). And, yes, mold can grow inside a paint can and be a serious health hazard if you put it up on your walls. However, if the paint has an ammonia smell, it's still good.
I wouldnt use it. It's gone off for 1 reason or another, and good latex paint should smell pleasant not foul. The bacteria are feeding off of the paint, releasing their toxic wastes. Return it for new.
If your old paint has separated but blends together nicely once mixed, its probably ok to use. *If your old paint is really chunky, it's too old to use. *If your old paint has a jelly consistency, it's too old to use.
Usually, about five years or more is fine . Paint in a sealed, metal paint can might last fine for well past 15 years , or more . I have seen it many times.
Most paints last one to two years in an open can. Latex paints can last an average of 10 years in an unopened can. Oil-based paint lasts up to 15 years in an unopened can. The paint goes bad by hardening or becoming rancid when air or debris gets into a can that isn't sealed well.
You might notice the consistency of your paint has changed. There may be a “skin” on the surface or lumps that won't stir out. If either of these is present, your paint has most likely expired.
One of the best ways to tell if your stored paint has gone bad is to test it on a piece of board or timber. If lumping occurs it could be that chunky sized bits of paint have formed despite a vigorous stir. Extreme bad smell like rotten eggs might be highly concentrated.
“We do not have expiration dates on [Sherwin-Williams] paint but we do give it a shelf life of three years (most architectural coatings) from the time of manufacturing,” says Sherwin-Williams' Director of Product Excellence Dennis Fiorilli.
Paint Shake and Re-Tints
If you bring your old paint to a Home Depot paint center, you can have it shaken up in their machines. This saves the effort of stirring up your old paint, but it also sets up another great service: paint re-tints.
I coated an entire smelly acrylic painting with bleach and let it sit. Now, the smell is gone! I've painted over it with new paint and all seems fine. This solution saved me for now, but my advice is to take a sniff test before you work with old paint.
Recycling Your Paint
Sherwin-Williams is pleased to volunteer many of our stores as drop-off locations. Ready to drop off your leftover paint? Search for a Sherwin-Williams store* in any of the participating states/jurisdictions.
What happens if you use expired paint? If the paint has a bad smell, you'll be adding that odor to your walls. In addition, expired paint will not provide even color coverage, the finish may not be smooth, and the paint is more likely to crack or chip.
Don't use old paint if it smells like rotten eggs and sour milk combined. Just don't.
Just placing a bowl full of baking soda in the painted space is enough to enjoy a room free from paint odor. Like charcoal, baking soda also has the property of absorbing bad odor. It is useful in eliminating even the strongest paint smell.
Signs of damage:
If it smells unpleasant or you see mold, you will need to discard it (correctly). And, yes, mold can grow inside a paint can and be a serious health hazard if you put it up on your walls. However, if the paint has an ammonia smell, it's still good. Give it a good stir and try it.
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.
Many contractors are impressed by the fact that Sherwin-Williams has more than 140 years of experience behind them, which means they've had a long time to perfect what they do. And they've done it well, as they are among the most trusted suppliers of quality paints in the industry.
In most cases, an opened can of paint lasts between two and five years. If stored carefully, it may last even longer. However, the storage environment, temperature changes and other factors can impact the shelf life.
All nontoxic pigments will be marked with a circle and the letters “AP.” If you see this circle with the letters “CL” inside then that is a toxic pigment and should be handled with care. Examples are cadmium, cobalt, and lead-based pigments.
Other types of paints, like latex paints, have lower levels of VOCs but can still be dangerous if not used properly. In general, paint fumes will remain toxic for up to a day after the paint is dried.
If your paint doesn't have a spoiled odor or consistency, you can use it for touchups or new projects—though it may not result in a perfect finished product. "The product might be too thick to apply, and not flow and level to an even finish," says Edrosa. Skinning is another concern with older paint.
With our wide selection of paint by Sherwin-Williams, HGTV Home® by Sherwin Williams, Valspar® and STAINMASTER™, your perfect color is waiting for you.
Impacts on Texture and Finish
If the paint is too thick straight out of the can, it may need to be thinned using the appropriate thinner (water for latex paint, mineral spirits for oil-based paint, etc.) to reach the right consistency.