paint thinner

noun2

1. •
   Any of several solvents used to thin oil-based paints or to clean up after their use.

   • Pour a solvent such as paint thinner, mineral spirits, or a liquid sandpaper product in a metal can or enamel bowl. Wear protective gloves. — 2004
2. •
   (humorous) Rotgut; especially, distilled rotgut.