Barkeeper's Friend Scratched My Aluminum
I'm posting this just because I didn't think this could actually happen or was even a concern, and I think other people should know. I received a new baking sheet yesterday, and I had a hard time getting the adhesive from the label off of the sheet. So, I scrubbed at it with a little BKF, and as a result the area where the BKF was is now scratched up (it had a mirror finish before) and darkened in color.
I've always had BKF recommended for using on non-anodized aluminum, and I use it on SS all the time without problems, but I've never seen this happen before. (The only aluminum piece I've used BKF on before was already damaged because my partner put it in the dishwasher.)
I definitely won't use BKF on aluminum again, and I am going to contact the company too.
The thing is, people are always recommending BKF for aluminum. The BKF website even recommends using it for uncoated aluminum. I don't think in that case my expectations (that it not damage things) were too high. I posted this, though, hoping that other people won't make the same mistake I did.
From now on I will just use soap and water, maybe cream of tartar if necessary.
Sorry you learned this the hard way.
BKF is a good product, but it is not advised for high-polish surfaces, especially softer materials like aluminum and copper. Bon Ami is a much better choice.
One of the unfortunate things about BKF is that it has an abrasive grit size larger than BA, Comet, Ajax, etc. If the user is scrupulous about just applying a slurry of BKF and not scrubbing much, you can be OK. However, human nature being what it is, when a stain or gunk proves stubborn, the user is tempted to scour with BKF--and most users succumb. Fine scratches can result, which are problems only until the entire piece gets the same "treatment".