Hydrofluoric acid, GR 40%

Hydrofluoric acid is classified as a weak acid because of its lower dissociation constant compared to the strong acids.

H 1530 (OTTO) Hydrofluoric acid, GR 40% Cas 7664-39-3 - used by some collectors of antique glass bottles to remove so-called 'sickness' from the glass, caused by acids (usually in the soil the bottle was buried in) attacking the soda content of the glass.