Be sure not to have anything dry-cleaned! Perc is still the solvent of choice for that.
By far, the best solvent for head cleaning was Freon TF (R-113)--now banned since the 90s for ozone depletion potential. HCFC-141 was offered for a time as an alternative (I still have bottles of KyRead where it's used as the vehicle) but that's been banned as well. HCFC-225 (AK225) is scheduled to be banned on January 1, 2015, so stock up--not that it's inexpensive to start with.
Interestingly, a suggested substitute for HCFC-225 is Trichloroethylene, which is really nasty stuff, particularly when encountered as a soil and water contaminant. I expect that the EPA will get around to banning that one also.
As far as tetrachloroethylene (perc) goes, the jury is still very much out on its property as a carcinogen.
Would that the EPA take the same attitude on CO[sub]2[/sub] as it does on fluorocarbons.
I've cleaned stubborn heads with acetone--but be careful--it can murder plastic.