Actually you are supposed to use new ATF on the seals.
Once you've pulled them, you are supposed to replace them.
Pep Boys, sells the seal kits - $2.50 each (something like that)
I did a tech article on it, you can find it here:
http://www.pelicanparts.com/techarticles/944_fuel_injector_clean/944_fuel_injector_clean.htm
AFJuvat
Meine Mutti fahrt ein chevy nicht! Sie gefahren ein Chrysler