Hmm, the snapping the strings idea is interesting. I'd imagine it loosens the caked on dirt and goo that is stuck between the windings which dampens their ability to vibrate.
I play on all Spiros with a Stark E detune to low-D now, but I used to play on Obligatos, then Dominants, then Evahs. I noticed they would all die a rapid death around the 1 year mark. They'd have harmonics slightly off-tune and sound really dull and flabby.
I clean my steel strings by loosening them one at a time so they'll bend in an "S" between my fingers and run an alcohol soaked face cloth up and down them until no more dirt comes out. Bending them opens the gaps between the winding so the alcohol can dissolve the dirt and lift it away. I've had my Spiros on for 3 years now and they still sound and respond great.
I've never tried this on a synthetic string though. I don't know if the liquid would get into the micro-filaments of perlon and do something weird to them. Might be worth a try.
I would think snapping the strings would break some of the micro-filaments causing off harmonics, etc.