Jesse,
If the containers used are important to you and you need to recycle them, the best way is to get a tin can with at least 3 to 4" opening and used it as your "dumping can". What I mean is, you let the mixing containers run empty into that tin can and when stop dripping use a little bit of acetone to wash them slightly. I achieve that on my glass pouring jars but adding about the amount of 1 soap spoon (depending on jar/container size) of acetone put the lid on and shake it a bit, this dissolves most of the resin out. Use that same dumping can to empty the used acetone into.
There are 2 things that I suggest you to do, if you decided to use a dumping can/tin container;
*- Do not put any tight lid on it, if anything use a small timber board just big enough to cover the top.
*- Keep it away from flames.
With time, the acetone will evaporate and what is left is resin crystals which are solidified bits of resin.
You can keep adding a bit of water on the tin, to prevent some ignition, this will not work while the acetone is active but, that acetone will disappear fast and the water will cover the left over resins making them safe(r).
The truth is, these left overs and other used utensils or disposable items use, such as gloves and paper towels previously soaked with acetone or other chemical, have to be disposed somewhere. The "common" rubbish bin is not the safest place to put them nor the flashing down in the toilet is either so, some attention should be given when disposing this king of stuff, all is extremely inflammable and should be handled/disposed, taking that into consideration.
Better safe than sorry, huh...???
Cheers
George
