3 in 1 oil would be ok, just a few drops, spin it by hand wipe it off and drop it in.
That is for sure the truth... I have put in a new one before and its come apart a year or so later, so its a good thing to just double check it since its easy to get too
When you replace the ignition switch, use super glue along the line where the plastic and metal sections mate . Be careful not to use too much and it will work great. The switches tend to come apart because the snaps don't hold the two halves together.