The metal tools work much better. They're available at Sears, Harbor Freight, any auto store, etc. Spray out the connection with Brake Cleaner, only get the kind without chlorine. That'll get most of the gunk out. You've really gotta get them in right, the fittings are a pain in the ass. If you're trying to get them off of the fitting right under the motor, good luck. They're the hardest due to they amount of road grime they get in them.