We’ve seen acetone used to smooth out 3D printed objects before – either by dunking the parts in an acetone bath or brushing the solvent on – but these processes had mixed results.

Smoothing ABS prints with acetone vapors can look amazing but results ... If you take some resin to use for 3D print smoothing, do not return it to a printer’s reservoir or container.

3D print firm Shapeways has a blog with a link to an interesting video in which a nylon print is sealed with a mixture of acetone and super-glue. I have no idea if acetone does anything to the nylon – ...