8 EASY Ways To DRY OUT Paint Cans For Disposal (How To Harden Paint)

Want to know how to get rid of old paint, safely? Here’s 8 EASY & FAST ways to harden paint cans and dry out paint for disposal, quickly!

How To Dry Paint Cans For Disposal

Somehow, every 5 years or so, I end up with a big collection of old paint that I can’t, or won’t use anymore. And, while recycling paint is great, the closest drop off for me is a 1/2 hour drive away.

So, it doesn’t make much since to try to recycle small amounts of some mismatched paint by driving so far to do it.

Luckily, there are some pretty cheap and easy ways to harden paint for disposal. In fact, you probably already have some of the things you can use to dry up paint.

Let’s get to that list of ways to dry out old paint for disposal.

How To Dry Out Paint Cans For Disposal (Video Steps)

Want to see how I tested these methods? Watch this video for a look at 6 of the ways you can dry paint cans for disposal. Scroll down to see the written list and tips.

Testing 6 EASY ways to DRY Paint Cans For Disposal (How To Harden Paint)

How To Harden Paint For Disposal

After checking the EPA recommendations and my state and local recommendations to safely dispose of water-based paint, I decided to test some of the recommendations to see which would work best.

Here’s how those tests turned out.

1. Kitty Litter

Every environmental waste recommendation website I checked recommended using kitty litter to harden latex paint.

And, I have to say, it was probably the best way to dry out paint cans quickly. Kitty litter works on water-based acrylic wall paints too.

For this test I poured generic clumping kitty litter into a half empty can of latex paint. Then, I used a paint stick to mix the kitty litter into the paint.

You want to mix it up well so that there is kitty litter mixed in with all of the paint. If it’s easier for you, you can pour the paint into a large, trash bag-lined cardboard box before you mix in the paint.

Once all of the paint is mixed into the kitty litter, let it sit in a dry place, or in the sun, so that it can completely harden. Mine was AS HARD AS CONCRETE in less than a day.

2. Sawdust

If you have a saw or two that gets tons of use, you probably have a HUGE bag of sawdust. For this test, I mixed 2 full drink pitchers worth of sawdust with about 2/3rds of a gallon of paint.

I had high hopes for this test. It seemed like sawdust would be a good way to solidify paint. But, after 2 days in my shady garage, it was still pretty wet.

So, I moved the paint and sawdust mix into the sun, on my driveway. Within 12 hours, that mix was completely dried out.

I highly recommend that you put your sawdust and paint mix in the sun right away to shorten the dry time.

3. Newspaper

Here’s another cheap, fast, and easy way to dry up paint for disposal. If you still get a newspaper, or newspaper ads, you can tear those into small pieces to mix into your water-based paint.

Newspaper is a pretty good way to harden paint for disposal. I mixed newspaper with paint then put it out in the sun. Within a day, it was completely dry and ready to throw out.

4. Plaster Of Paris

I didn’t see Plaster of Paris in my research as a way to get rid of old paint. BUT, I use plaster of Paris with latex paint to make DIY chalk paint. So, I know that using too much of it can dry out paint in a cup.

So, I grabbed my cheap carton of Plaster of Paris and poured a cup or more into my leftover paint. Then I stirred it up and left it sitting in my shady garage.

After 2 days, the paint was still pretty wet. So, I placed the mix in the sun. After 12 hours in the sun, the mix of Plaster of Paris and latex paint was completely dried out and ready for the trash.

Whenever possible, place your mix of paint and whatever you’re using to harden paint in the sun to harden it faster.

5. Air Dry

Two of the Environmental Waste websites I checked mentioned that 1″ of paint or less could just be left with the lid off. Then the air was supposed to harden it within 3 days. So, I gave that a try.

I left my can open for 3 days in my shady garage. BUT, it was still REALLY WET under a thin skin of dried paint. So, I popped it in the sun to dry it out faster.

I’m sure the paint would have dried out without the sun, if given a week or more. BUT, I want fast methods.

And, even with a lid off, a full gallon of paint will need to be left open for a month or more to completely air dry. So, this was my least favorite method, even though it technically works.

6. Store-bought Paint Hardener

Of course, you can always buy store-bought paint hardener to dry out paint in a can. It sells for around $4 for a package that can harden 3/4 of a gallon of paint.

BUT, if you have 10 gallons or more to do, that can feel like a waste of money. SO, I recommend buying a BIG, CHEAP container of clumping kitty litter to dry paint instead. It works just as well.

7. Sand

I didn’t have any sand to try this method out, but a few websites suggested adding sand to your paint can to dry paint out for disposal.

Again, I can’t say whether or not it works. But, you can always try it with 1 container of paint to see if it works. I recommend leaving that paint and sand mix in the sun, to help the paint dry out faster.

8. Slow Pour

Here’s another completely safe way to dispose of paint. BUT, it might take a LONG time, depending on how much paint you have.

For this method, grab a big cardboard box, line it with a trash bag to prevent leaking, then pour in a thin layer of paint. Let that dry completely, then repeat until your paint is completely hardened.

How Do I Dispose Of Paint Safely?

To safely dispose of water-based paints (latex and acrylic) you just need to harden it before throwing it in with your normal trash.

Water-based paints are non-toxic and NOT HAZARDOUS. You just need them to be dry to prevent them from contaminating soil and water.

How Long Does It Take Paint To Harden With Kitty Litter?

Paint mixed with kitty litter can harden in anywhere between 1 hour and 12 hours, depending on how much kitty litter you use and the weather.

It will take a little longer for larger 5-gallon containers of paint to harden in cold weather or high humidity.

Setting the kitty litter and paint mix in the sun can help to dry out paint cans quickly. Spreading it flat on cardboard or a trash bag can also speed up the dry time.

How Much Kitty Litter To Dry Paint Cans?

I use 2 to 3 cups of clumping kitty litter to harden 1 gallon of paint. Just be sure to mix it well to be sure that all of the paint hardens. When you mix it together, it’ll look a bit like thick oatmeal.

That’s it for how to harden paint for disposal. I hope this helped! Now, here’s a few more posts you might like.

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