I was reading another thread about failed anchors use for a safety cover and thought it might be wise to do a little maintenance on mine. Mine go into concrete so I’m not concerned about them coming loose, but I do want to keep the threads clean so they don’t seize. I was thinking about taking each one out (the part that screws out) and blowing out any dirt from the shell. Then I’d like to lubricate the threads as I put them back together. Therein lies my question. What type, if any, lubrication should I use?