Acetone is a useful solvent for the plastics industry. Furthermore it has many general purpose uses, and is quite safe to humans in small amounts - it is not dangerous unless exposed to fire or ingested. It can be purchased at the grocery store as Nail Polish remover. Small amounts of Acetone evaporate when exposed to air.
Acetone is flammable. Store Acetone in a closed container. Dirty Acetone can be saved and re-used until you deem it is too dirty. It is not corrosive in small amounts, and does little more than dry human skin (though keep away from open wounds). For full details of the health and safety of Acetone refer to a MSDS/SDS.
How to Use Acetone
Acetone can be used to clean off many kinds of uncured and cured plastics and polymers from tools. Tools can be soaked in an acetone bath over time. It is best to cover any open containers of Acetone, as it both evaporates, and is flammable.
In cleaning a concrete floor, for example, Acetone can be used as an alternative to water as it will evaporate quicker. This is done when preparing a concrete floor for finishing (epoxy, urethane, etc).
Acetone can be used to clean resins off of hands or surfaces. Simply apply, and rub the acetone in, until the resin is dissolved in the solvent.