I've got an old snaffle bit that appears to be in good shape other than being completely covered in rust. Using the steel wire brush on my bench grinder, I removed all the rust I could get to. The only areas I could not get to were in the middle of the bit where the two pieces fit together and the areas where the rings go on the end of the bit. The amount of rust that is in those areas is very minimal, and the rings and bit parts move around freely. After using the steel brush, I used WD40 to clean it up, and then used Joy dishwashing liquid on it (to remove any oil) and rinsed it thoroughly. I am attaching pics of the bit when I was half done with the grinding, then completely done, and then a close up of where the inside of where the bit fits together.
My questions is: Is it safe for me to use this bit even though it may have a tiny bit of rust that I can't get to? Please let me know what you think.