Hi there. I've picked up some Vallejo liquid mask, thought I'd give it a go. I also picked up (by recommendation) a cheap spray gun and I'll run it from my large compressor. I've googled and tubed and I can't find any information on thinning or cleaning. Does this stuff need to be thinned? If so what with? And what do I need to clean out the spray gun and bottle after? Many thanks.