Now when there's paint left over from a job, I consolidate it into smaller, clean containers, and clean the paint out of the rim before I tamp down the lid. For touch ups I find that it's handy to have paint colors from each room and hallway, extra ceiling paint and a spare pint of ultra pure white semi gloss. I like to freshen up the window sills once a year...they get a little grubby with the dust in our city air.
I guess you could poke through that thick layer, but....don't do it.
This is so gross, I had to dig it out to show you! I'm sure it will cross my mind the next time I order flan for dessert...
You can buy spare quart, half gallon and gallon-sized paint cans and lids at a home improvement store. Like Tupperware for your leftover paint! You'll keep the paint fresher and you'll save on space. Write the room brand of paint and color on each can and lid with a Sharpie.
I have a Home file where I save the "paint chips" from the paint store, so it's a snap to have more made up. Simply jot down the finish at the time you first buy the paint--eggshell, satin, flat, semi gloss or high gloss--so you don't have to guess.