"Brass and other alloy plating"

Beginners should probably avoid brass and other alloy plating. Virtually all brass plating is done from terribly poisonous cyanide-based solutions; and cyanide is not only poisonous to ingest, but accidentally acidifying cyanide solutions can release deadly hydrogen cyanide gas into the air.

If you can find a proprietary brass plating solution which is not based on cyanide it may be safe to use as directed, but you will still have the problem that alloy plating is very tricky business (brass is an alloy of copper and zinc). The reason is that copper is a quite noble metal and zinc is a quite active one (note that children make lemon batteries, which generate more than a volt, simply by putting a copper penny and a galvanized nail in the lemon). The copper steals electrons from the zinc, pushing it back into solution while copper deposits to take its place.

How are you going to deposit any zinc at all when any copper in the solution will instantly push the zinc metal back into solution so copper can deposit on the article instead? Alloy plating requires powerful complexing agents which "tie up" the more noble metal (copper in this case), allowing the more active metal (zinc in this case) to deposit.