Techs hate the canned air or flat fix stuff because the accelerant that forces it out of the can is flammable and explosive. It can cause the tire to explode when you run the hole reemer through the opening and it sparks against the steel belt of the tire.
My cousin nearly died fixing a simple flat tire. It was a slow leak and the guy kept puting "Fix-a-Flat" in it including a few minutes prior to stopping to have it repaired. The explosion was heard up to 5 miles away. In fact, the workers in a factory about 100 yards away from the garage were evacuated from their building because they thought the explosion was there.
Bottom line; If you feel you need to use it, ALWAYS tell the technician that is going to work on it. If you're going to work on it, empty the air out of the tire, refill it with compressed air, repeat and finally refill to purge the accelerant.
Ok, done now. Sorry for the rant. Continue on.
