I've used a similar method for years to eliminate surface marks such as spotting and including slight scuffing that can happen accidentaly when removing loose dust from the surface of some glossy emulsions. The difference is that I hold the mounted print about 12 inches from a jet of steam coming from a kettle as it boils. The print is moved around continuously so as not to allow heat to build up in one area and to make sure that the whole of the surface area is treated in the same way. The print surface should not be touched until it drys, it takes only a couple of minutes, and the end result is that all surface marks disappear and the print takes on slightly higher gloss. I accept that this method can be described as risky but with a little practice on reject prints you will soon get the hang of it. I melted the emmulsion on the first print that I ever tried this on, unfortunately it was not a reject so I had to go back to the darkroom and start again, since then I've had 100% success.