What is in glass etching creams?

Things found in etching creams: Barium Sulfate, Sulfuric Acid, Sodium Bifluoride, and Ammonium hydrogen difluoride.

Hydrofluoric acid is the main ingredient that will etch glass. Overall, the cream is a diluted form of hydrofluoric acid. It's not nearly as dangerous as pure hydrofluoric acid but still, be very cautious when using it.