The problem is that old paint has coagulated paint inside. You know, paint chips.
It’s easy to strain them (just below) but before you bother, the paint may be bad, so read the section below called ‘Paint Gone Bad’.
How to strain old paint
Remember, latex paint can be easily washed from a strainer. I reuse them many times.
- Grab a lady’s stocking* or
- Professional strainers: they are very low cost: single-use cone strainers or a big strainer bag for big buckets
- Situate the strainer over a clean can (empty) and pour paint
- Fill the bucket as high as you like
- Remove the screen, and rinse or toss the strainer
*Make sure they are stockings without holes or runs.
Paint Gone Bad
You must check: don’t assume*. Smell it.
If it smells rancid or moldy it’s bad. Get rid of it. Don’t put that in or on where you live.
A full post on this topic is here, but the short story is:
- Many old paints had glycol as an anti-freeze, but if it could have frozen, it’s likely bad. (In the garage?)
- If it is latex and at some point, it may have frozen, it’s going to look like cottage cheese or just stink. Use a paint solidified (linked just above) and put it in the trash or ask your local recycle company/city if they can handle it.
- If it’s oil, it may still be ok. You’ll have to do what follows and do some testing, which will take time. Don’t rush this. You don’t want to have a bad wall of oil paint. Ick.
* When you assume you make an ass out of Uma Thurman! (Thanks Al.)
Why you need to strain (almost) all paint
Once I bought a 5 gallon pale of paint that had dried particles. It was on the shelf in the store for too long!
What I do:
- Any paint, old or not so old, should be strained. New paint: up to you but read that line above!
- Even paint that was put back into the can may have lint from an old (budget) roller cover or just dirt.
- I even strain my new paint after it’s been in my working can for a few hours. The edges of the can dry and create chips that need to be strained out.
- The store-bought strainers are much faster and remove everything that stockings do. But stockings are free… but slow.
Here are the tools I use. Strainers are about halfway down under Sprayer Accessories. ( A must for sprayering paint). Just have some on hand.