MO-probably the best stuff for iced guides that i have used.Yea first time i have heard of it damaging fly lines,supposed to take off the coating and the line will crack,I'm thinking my line is just fine.The ad for the Mucilin says don't use it on fly lines. Of course in Ohio we have no trout and no bass and very very small pan fish so we don't fish much,therefore we don't need to replace our gear often.
Ohiotuber can attest to that,I don't think Mike buys anything.

Life is good
Mike