Hard to guess what’s going on without actually watching. Generally, if you get metal from a BATT lap, it isn’t charged enough. BATT can absorb a lot of diamond when first put in service. I did have a stone a few years ago which scraped metal off the lap at a particular angle, but that turned out to be my fault.
I always found baby oil to be too viscous. I like WD-40, though some people can’t stand the odor. There are lots of choices for lubricant. Trombone oil is reputed to be very good. Gearloose’s Snake Oil (approved by Professor Ignatius) is great, though pricier than common oils.