I was using was the green Scotch Brite pad that you buy at the super market in three packs to clean the top of my Lower Intake Manifold(LIM). I didn't realize but a little dusting of the Scotch Brite pad was going down each LIM hole. I thought the Scotch Brite pads were harmless. But then I read the internet warnings. They have aluminum oxide in them. There's no way I'm taking that LIM off. I'm sick enough of working on this car as it is. I just tried to fish out as much dust as possible with a magnetic pick-up tool. I zip-locked a paper towel over the end of it and soaked it in carb cleaner. Then I went fishing and got some of aluminum oxide dust. I guess my car will be a case study for how long an engine lasts after sucking in some Scotch Brite dust. Some people debate that Scotch Brite dust actually harms an engine. I guess I'll find out the hard way.

 

While no one wants anything more than air & fuel going into their engine, I don`t think you need to worry too much about it. The green pads are very mildly abrasive. I use the red ones here for cleaning aluminum with & other things & they are more abrasive than what you are using. More than likely if & when the fibers get sucked into the engine, they`ll just get blown out the exhaust pretty quickly. With the higher exhaust temps of the rotary, more than likely they will be vaporized when the fuel ignites anyway.