Boeshielded the 170 a few weeks ago... it wasn't that bad. I picked up a spray gun at Harbor Freight for like $6 that was the ticket. No dorky 12 foot wands, this thing was a blast-fogger. It takes a standard air fitting, has its own reservoir, and an adjustable venturi tip that can produce a fine fog or a super douche blast. Poked it down the wingtip and fog came out the root, so with a few blasts here and there in the inspection covers, the wings were done.
Shot it in every nook and cranny on the airframe, vert and horz stab and all the control surface corrugations. The fun part was washing the smegma off the outside of the plane a few days later.
I recommend this easy preventative maintenance to anybody, whether you have a Cessna or a rag/tube job.