Stephanie Lee at Semi Precious Salvage has posted a tutorial on etching brass using hydrogen peroxide and muriatic acid.
See Stephanie’s method at Stephanielee.typepad.com.
Read more about muriatic acid here.
Read the Wikipedia entry, most especially the safety section, here.
MUST READ: always read the MSDS (Material Safety Data Sheet) before using any material or chemical. Read the one for Muriatic acid, aka hydrochloric acid, here.
After reading the MSDS sheet, I think I’ll stick to etching with ferric chloride, but for those of you with access to a safe setting for the stronger acids — such as an acid fume hood at a college — I’ll post this information anyway.