This is a pretty simple table: it goes inside a taller semi-disposable container, and holds parts over a vat of acid (vinegar + salt) while they form a patina. I use it to make copper & bronze look older.
Should be super easy to print, and usage is kinda obvious too :)
update: added a smaller one for 2oz plastic cups, I got a lifetime supply from a restaurant supply store. Works great for smaller parts in weird mixes (like 1 part over ammonia)