There is a thread on here somewhere about using a solution of 1 part molasses to 20 parts water as an electrolyte. You can drop your rusty item in it and leave it for a month and all the rust dissolves. Alternatively, you can hook it up to a battery charger with another piece of steel in the solution and the rust dissolves in a day or two. You need to be careful about which terminal the door or item is attached to but there is plenty of info on this to be found by doing a simple search either here or on the net generally. eg battery charger method
https://www.youtube.com/watch?v=C83xMYAnCOI -
and molasses method
https://www.youtube.com/watch?v=vq5IUiYMhRM - good Aussie video
I'd be interested in how you go; it's on my hit list as well.
cheers gerald