If your old bottles of Testors model paint dried out, you’ll have trouble getting the jars open and there’s no guarantee what you’ll find inside. But it’s definitely worth a try.
Here’s how to get the lid off, what to do with the separated paint, and what you can do to keep it from happening again.
Open a stuck jar
If the jar is stuck shut, try wrapping a rubber band around the lid. Sometimes this gives you just enough traction to be able to get the lid open.
When that doesn’t work, I use a jar opener. These are marketed toward seniors with arthritis, but when it comes to dealing with dried paint sealing a lid shut, I wouldn’t blame King Kong for using one of these. I’ve been using one of these openers since I was 30, and on more than just paint. Buy one. You’ll be glad you have it.
When the jar still won’t open even if you stuck it in a vise and tried to turn it with a jar opener, there’s one last-resort fix. Turn the jar upside down. Then use a small paint brush to dab a small quantity of lacquer thinner under the lip of the lid and let it sit for a few minutes. The lacquer thinner will soften the paint that’s holding the lid closed. After a few minutes, you can probably get the jar open. It’s OK if you still need the help of the vise and the jar opener.
When you’re messing with lacquer thinner, use it outside, don’t breathe the fumes, and don’t get the lacquer thinner on your skin. It’s nasty, dangerous stuff.
Lacquer thinner also costs more than a new jar of paint, so it’s not worth buying a pint of lacquer thinner to save one jar.
Reviving separated Testors paint
Once you get the jar open, there’s probably usable paint inside. I have jars of paint that I bought in 2004 I can still use. If the paint is completely dried out, there’s nothing you can do. But if the paint is just separated, you can bring it back.
Drop a brass washer into the jar, then replace the lid. Use brass, not steel. Next, shake it up just like you would a can of spray paint, alternating between shaking it up and down and spinning it in a circle to scrape up the pigment in the bottom. Alternating between shaking, circling, and shaking again for 3-4 minutes will usually mix the paint back up enough that you can use it again. I find it easier than stirring.
Leave the washer in there; if you repeat this ritual each time you use the paint, you’ll get better coverage and truer, more consistent color. When you use up the last of the paint, fish out the washer and use it in your new jar.
Preventing stuck lids and dried out paint
The old adage that an ounce of prevention is worth a pound of cure definitely applies here. There are two tricks that can keep a jar of paint good indefinitely. I’m talking decades here. You just have to remember to do it, which I don’t always myself.
First, wipe the threads of the jar and the threads of the lid after you use the paint. Some paint probably got on both when you shook up the paint. Clean that off, and then you won’t have paint on the threads to glue the lid shut. Also, paint on the threads can keep you from getting a good seal, so the paint inside the jar lasts longer too.
Second, wipe a little bit of petroleum jelly or grease onto the threads of the lid. This helps seal out air, so the jar doesn’t dry out as easily. If you missed a little bit of paint, the paint won’t stick to the lubricant. And finally, the lubricant makes it a lot easier for you to reopen the jar. You don’t have to apply lube every time you use the paint. But if you’re not sure when you did last, go ahead and put some on the jar. It won’t hurt.
A jar of Testors costs around $2. That’s not a ton of money, but the cost per ounce is higher than most paints, so you might as well make those jars last.