I think you got it mixed up. Naptha or commonly known as lighter fluid, is used to remove the residue glue on the surface after the velcro is removed. Do not try to apply the fluid on your pedalboard and proceed to detach the pedal.
1 suggestion is to use a flat head screwdriver, slowly prod at where the velcro and board meets and "pry" it out. If possible, remove the rubber base and attach the velcro next time to the metal surface of the pedal. Reason being, the velcro stuck to the rubber base after some time....it will smudge it with the glue residue, or like now it will just rip the rubber out of the pedal when detaching it from the board. Hope that helps.
