Hi fellows, I'm using Heveatech decking on my balcony, & it's varnished with a few coats of wood varnish. I do some gardening in my balcony & soiled (literally ) water splashes on the decking every now & then. It stains the decking such that using plain water & melamine sponge (that common white "magic" sponge) doesn't really remove the muddy stains. I don't think I can use thinner/turpentine because I presume those solvents are meant to strip paint. What may I use to clean varnished decking? Anybody care to share some experience?