I use Rabbit Skin Glue, an animal byproduct, as a size on my linen canvasses to keep the oil from the primer and oil paints from rotting my linen. During rainy season I probably should spray the backs of my canvasses to prevent bacteria or fungus growth from forming. Does anyone here have any first-hand experience with this? Or, know of anybody who has? Should I wait until it happens, or spray those canvasses ahead of time? Please do not suggest taking them down to the local mortuary and having them cremated--haha. Thanks.