Two days ago at work, I was using the polishing machine to get rid of the oxidization on a pendant. While I moving the piece side to side, the chain on the pendant got caught into the machine as it was spinning. Don't know how it happened, but I guess I wasn't so alert. Luckily, the chain just slashed my left hand a little bit and it didn't slice my finger off. I talked to some my jewelers yesterday and they told me scary stories about using the polishing machine. I never knew how dangerous the machine was. So long story short, never polish something with a chain attached!! Also, protect your eyes and hands!