Re: testing painting - is it oil or acrylic - I forgot!
Cotton ball with alcohol, rub a dub dub. If paint comes off onto the cotton ball chances are good it is acrylic. Sometimes, you can tell by taking a whiff of the painted surface. Not always a good way but if it smells of linseed oil, chances are it is oil.
You might consider writing, with a pencil, on the back of the canvas denoting what was used.
Another idea is to add a bit of nomenclature to the serial number. i. e., AC acrylic on canvas, OC, oil on canvas, kind of thing.
to go to the information kiosk My You Tube Channel 48hlc48
"When you were born, you cried and the world rejoiced. Live your life in such a manner that when you die, the world cries and you rejoice."