TomG shows how he etches PCB boards using paint, a 25W laser cutter, Muratic Acid, 30% H2O2 and a sponge. Much frothing ensues.
The technique is a neat one, given the presence of a laser cutter, because it can take you from copper clad to etched board in a pretty quick amount of time.
One note, the Muratic Acid is actually from a pool supply store, not Home Depot. It is, of course, dangerous. Wear safety goggles, use gloves, use in a well ventilated area. (The acid smells like a punch to the nose, don’t inhale it)