Has anyone out there used Xylene/Xylol instead of paint thinner or mineral spirits? I used to clean foam brushes with paint thinner after varnishing, with the thought that I could reuse brushes. But I noticed that a thick waxy goop built up on the brush if left in the thinner/varnish solution for a few days. Switching to mineral spirits improved the situation, but there was still 'wax' on the brush after a while. I then tried Xylene/Xylol. Wow - what a difference. No waxy goop at all even when I leave the brush in the thinner/varnish solution for a few weeks! So now I use Xylene/Xylol to thin varnish as well and have noticed no problems. Does anyone see a problem with Xylene/Xylol? And I've just tried this: I have a half empty can of varnish that I know will develop a 'skin' by the time I need to use it. So I've just poured maybe 1/4" of Xylene/Xylol in the can and didn't stir it. I'm thinking that the thin layer of Xylene/Xylol will act as a barrier between the varnish and air in the can which should prevent skin formation & thereby extend the life of the varnish. Thoughts?