Cheers for the input guys its deffinately doing a good job of putting me off the process, I was going to use S.p.l as they are only an hour away but I think I might reconsider, you may have just saved me thousands
HouseAtreides was telling me about soda blasting a couple of weeks ago I'm thinking maybe this might be a safer method.
i was mainly concerned with any blasting that your only getting where the gun can get but I guess they only seem to rot in certain places and those places are usually where the weather and road salt etc can get so do the crevices you can't get to really matter, after all the car is 22 years old and only has isolated rust spots. at the end of the day if it ain't broke why fix it I suppose.