Well, there is the sublimating (self-dissipating) spray from the German company, but it is very expensive (some $50 for a can about 16oz).
Some people have used Dry Shampoo (not very expensive) to good effect, especially if trying to scan hair.
I have read that talcum powder combined with rubbing alcohol works, but I have not seen a recipe for the best ratio.
A washable chalk spray (the Testors brand seems most economical) is also used. They come in a variety of colors and, more importantly, prices, so be careful where you are shopping. Four 6oz cans can be had for $16 in places like Home Depot, but over $30 on Amazon (although that does include free shipping, while the Home Depot price is in the store). Montana Brands has a spray chalk for $16 for 400ml (approx. 14oz)
I bring you my recent experience. I used the dry shampoo on the headlight of my motorcycle because I intend to create a custom windshield. The experience was also positive because it all cost € 3. Without it I couldn’t scan anything. The hassle is cleaning everything up afterwards.
I am going to try the taco with alcohol for large parts.
I have been 3D Scanning with various devices and software for about 6 years. I usually use dry shampoo if I need it. I get it from the dollar store. The biggest problem with it is that it comes off VERY easily. Just touching it will cause marks, which makes it difficult if you need to move the model around for different angles.