You’ll know these little cups from getting takeaway that comes with sauce on the side—small transparent plastic cups (usually around 60mL/2oz) with a clear snap-on lid. I use these cups for holding experiments I’m monitoring so I don’t waste higher quality packaging on something I mostly just want to watch and then probably throw away at some point. Wondering how long it takes for something to mold, if something will split, or if one thing is soluble in another? Mix it up in one of these, cap it, label it, and observe away.
I’d recommend getting at least 50 as they are very useful (it’s also hard to buy fewer than that!). You can find them on US Amazon & Canadian Amazon.