How to clean grunge off of porcelain

Put the porcelain part in a plastic bag along with a pan of ammonia. Use grocery-store ammonia at full strength. Let it sit for 24-48 hours and you will be amazed that the grunge and filth wipes off with little effort.

Who can fix or service my Waterman Stove?

You will need to find a repair shop that specializes in vintage appliances.  Since many Waterman stoves are found in the metro New York City area, a few options include:  Belgrove Appliances in Yonkers, Peter Natoli of Father and Son Appliance Repair in Brooklyn.  I have heard of others, but cannot recall their names – please let me know and I will include listings here.