Is the material actually cotton canvas or is it nylon? My WilderNest has a heavy nylon with a urethane coating on the inside, which actually presents a problem since most stuff that's good on nylon isn't good for urethane and anything that is safe for both doesn't clean tough stuff like grease or pine tar. Anyway, for routine maintenance I find that just plain old dish soap and a good wash and dry is sufficient. If it's stained badly, I typically don't worry too much about it, just clean and stabilize it to keep it from deteriorating the material or coating and live with the stains. I use rubbing alcohol mostly to spot clean. I have this stuff called Sail Bath made by Davis. It's a glycol based cleaner that is made for cleaning oils and salt from sailboat sails, which are mostly synthetic now. I think the stuff has been discontinued, so I dunno what I'll use when the last couple of bottles are gone. But it works pretty well and seems safe enough on my fabric so far.
