[danw]

I, too, have stainless pipes. I have not had the pleasure of removing baked-on microfiber from them, but I have encountered the occasional runaway plastic bag (and some other unidentifiable stuff…).
The most effective method I've found is to heat the pipes (generally once around the block will do it), then use a wood scraper on any thick layers. What's left comes off with Borla exhaust cleaner backed up by fine or medium grit bronze (NOT STEEL) wool. And the pipes are none the worse for the experience.