Cleaning the metal face of a Jeff Rowland Model 3

As the OP did, I called JR at the telephone number the OP provided and received the same advice from a nice persons at JR.  The person answering the phone passed me to a person in shipping who said they use that product: 
"spray it on and the stuff, tape and such, just comes right off".  I am not holding them to any responsibility if it doesn't work but was nice to know JR works like a small company where people all over the org will speak with customers trying to give a solution.  Thank you idfnl