Store the smaller amounts of paint in glass canning jars with those two-piece metal lids - and put the glass jars inside the old paint cans (padded with newspaper for protection) so you can keep track of which paint is which for touch up purposes. Try to fill the new containers right up, so an assortment of sizes may be need, even for one color. Tupper ware type containers will not provide the tight, tight seal needed for paint and consumer-grade plastic containers may not do a good enough job, long term with the solvents in paint.. You can also buy empty quart paint containers at Big Box paint stores.

The other thought is why keep it all; paint both inside the can and outside on the wall is constantly changing so after the first few years, it won't match well for touching up any way.

Alternatively, you could just get rid of the paint by donating it to someplace that will re-use it. They often take small amounts which they mix together into Heinz-57 colors.

If you must discard it in the trash most places ask that you open the cans and let it evaporate to a solid state before throwing away. It takes a surprising amount of time to evaporate the fluids out of more than small amount of paint.

Faron may chime in with a paint dealer's perspective, but I doubt that any plastic container would keep the paint from drying out.

L.

I started using the Ziploc Twist 'n Loc plastic round containers a few years ago. They come in two sizes. I xerox a copy of the paint info on an Avery label and attach it to the side. The paint remains fresh and this has worked out well.

I keep my smaller bits of paint in old pickle jars. See through so I can tell the color. I also mix odds and ends to create my own colors. I buy mistints or incorrectly mixed paint all the time and stock up for my next project I have multiple colors around just in case. At 5 $ per gallon it works out great when helping friends. I now buy all latex so they mix well.

Talenti Gelato comes in hard plastic one pint containers with screw-on lids and are perfect for left-over paint. We've been painting a lot lately, so we have to keep buying gelato to get the containers. Sometimes we match the flavor to the paint color.

I'd been saving up peanut butter jars and use them to store extra paint. I wrote the room the paint was used in, and the color code on the outside with a sharpie. Also wrote the sheen type, etc-because all too many times I thought I'd remember. HA!

I keep my paints on a shelving unit, and I like that since they're in clear containers, i can pick out what I want easily. I also keep a paint stirrer that attaches to my drill, so it mixes up the small quantities up very, very well and no problems whatsoever with touch ups.

I do keep the paint out of direct sunlight and excessive heat/cold (a well insulated garage is fine for keeping it from degrading). The size of the jars, and the fact that they're plastic seems to work well.

Old jars. I have a bazillion, I can hardly ever bring myself to get rid of a glass jar. And I usually will choose a product in glass over one in plastic for that reason, among others.
Size the jar to the amount of paint so there is little head room.

Well, it would take me too long to eat enough jarred food to come up with enough containers for my paint, so at the grocery store today I stumbled upon canning jars and bought a bunch. Can hardly wait to organize my paint! And I know how pathetic that sounds... :)

Canning jars are great! You can buy plastic lids for them too, much nicer than the rings. The giant jars, the 1/2 gallon and even the gallon, are wonderful.
I store all my flours and grains in them for the freezer.

You asked what we "did?" Well, I paint, then put the leftover paint can on a shelf in the "paint cupboard" and never open it again until a day like yesterday, when I thought "Geesh! All this needs to go to the hazohouse!" I save all the leftover paint from projects, but really, I should just have a 3 X 5 card with the #, paint number combination, etc... (or on the computer)! Those other folks? They have real ideas!! I always saved paint in the original containers so I could go back to the store and have them mix the paint.... which, again, I have never done!