Robla Black Powder Solvent Robla Black Powder Solvent loosens and removes remainders of black powder, soot and rust. It also removes oil and carbon particles clinging to the metal. Robla-Schwarzpulver-Solvent is particularly recommended for the cleaning of cartridge ejection systems in revolvers and the cartridge feeds in pistols which are highly susceptible to powder residue. Robla Black Powder Solvent will keep your weapon well-functioning, which saves you from anger and frustration.