There's not much doubt that the solvent is flammable. But the switch from a flammable propellant to CO2 may make it less suitable as a starting fluid. At 12:35 PM 2/16/2011, Charley & Peggy Robinson wrote: >It's easy to find out if WD-40 is flammable. Get a can of it and >spray it above a burning match. WHOOF or not. :-)