another vote for citric acid from me... use it all the time removing rust from vintage cars beying restored.
Another top tip is to try Phosphoric acid, this is the basic ingredient of things like Jenolite, it converts rust to Iron Phosphate stopping it in its tracks... pro-tip to save money -...
I changed my DL picture a year ago and was promised I'd be able to update online from now on....
Tried to change address and went through this whole thing like OP...
I do not have nor need a passport!! or maybe now I do it seems!? grrr