I've got a new to me 1919 OTCA that someone stained dark. They either did a bad job stripping it first or the original finish just has worn away. Most of the wood is bare but I can see some finish and lighter wood here and there. I eventually want to sand/strip/lighten the interior as much as I can but in the meantime would like to preserve and protect the wood. My thought is to use tung oil or boiled linseed oil. The canvas was redone about 5 yrs ago and is in decent shape. Will the oil make the stain harder to remove? Will the oil harm the canvas/filler/paint?