What color is the fabric? Test whatever you try somewhere where it won't show first. Heat excelerates chemical action. Most rust removers have oxalic acid in them. There are some rust removers in the consumer market. TEST FIRST.
We have had excellent success in this type of spot with a product called "Incrediable" The big box linen stores carry it on on the internet.
An antique dealer told us about it--and uses it in his restorations.
Darn! :sad
My excuse for going to Hawaii will be here in July and the graduation isn't until a year from November, so I guess I'll have to try something else. Everyone has given me enough ideas to work with. :thup