Originally Posted by Wassie
I have a painting I did a year ago and it is still wet to the touch. Why??
Wassie, most retouch varnish is thought to be made from dammar, which would mean you'll probably have to use turpentine. If you don't have any turps then try mineral spirits but it may not be strong enough to properly dissolve it.
Your retouch varnish might be made from a modern synthetic resin, in which case any mineral spirits will do fine.
A previous thread and some tips that might be helpful: Safe Damar removal
Using a lint free cloth dipped in [spirit], start in a small corner and gently rub the surface of the painting. The varnish will dissolve onto the cloth. If any colour is seen on the cloth then you must stop. Work your way across the entire surface of the painting in small squares. TIP: Keep using fresh pieces of cloth to ensure that the varnish is being lifted and not just spread.
If in doubt, give the painting one last rub with [spirit].
Golden (the acrylic maker) also suggest, for their MSA varnish, laying a solvent-soaked cloth onto the painting for a few minutes before you begin the rubbing procedure. Worth testing this out on a small area, see if it makes any problem with colour coming off on the cloths worse.