Any Sarcoid treatments that work?

My thoroughbred gelding has developed numerous sarcoids over the years, they are mainly up in his groin, a couple pea size ones on his sheath. AS he's getting older, they are growing quicker. The past two years have seen ones he's had for about 6 years double in size. Weather? Diet? I've had him to the Vet (vet school near Edinburgh) numerous times for treatment with liverpool cream and whatever else they do and they just keep coming back. Some do nothing once they appear, others have grown and dropped off, a couple have grown very large and ulcerated/weeped and then shrivelled up and dropped off after time. None of them have a stalk to put a tie around unfortunately, all are under the skin on a fixed base. They are the bane of my life! I know they will be the end of him one day, probably quite soon, but if there are any suggestions out there to keep them under control, and avoid more trips to the vet they would be much appreciated! My vet said not to bother with that Camrosa stuff, I've heard garlic does something to them so he gets tons of garlic everyday and garlic puree rubbed on them too! Which is good in the summer.