Many automotive aerosols spray a volatile liquid, so when ingested and subsequently combusted, will often offset the air leak, causing the revs pickup.
Brake cleaner is used, as it drys without leaving a residue.
I doubt you'd have any chance of igniting the spray, bar spraying it on a red hot manifold (even then...)
Before following your mates advice, trying pressuring the inlet tract with a air compressor / servo tire compressor. Look around (300ZX club) theres basic instructions on making a AFM sized plug (PVC end cap) with a tire valve tapped in; they're priceless and have helped many people I know.