A method is disclosed for preventing hardener compounds to be formed from hardener precursors in a sealed and pressurized aerosol can. This includes a paint forming dispersion containing after sealing the can a liquefied propellant, epoxy or/and polyurethane resins amount W1, hardener precursor of the epoxy or/and polyurethane resins amount W3, where the epoxy or urethane hardener precursors are selected from a group including an imine, an enamine, a Mannich base, a Schiff's base, an oxazolidine, an aldimine and mixtures thereof, free water of amount W1 in a range of 1-10000 ppm, and brought into the can alongside with the other paint dispersion forming chemicals before sealing the can. A catalytic compound prevents formation of the epoxy or/and polyurethane hardener amines from the epoxy or/and polyurethane hardener precursors: