3y back i sprayed a tree onto some scott p4s, just roughened the topsheet a little, with a bit of sandpaper, then gently removed all dirt and grease with a drop of acetone on a rag (be careful with thinners and shit like this, use it very careful cause it will "eat" through plastic in no time, or could make nasty stains ...)
then i just sprayed on the stencil , let it dry, then cleaned + roughened it again, and sprayed over
a clear coat, 4 layers, today the tree is still going strong, and i only had to do minor aesthetic patchups around the edge of the ski...