Here is what msper is working with

My first suggestion, working from the safer products to later maybe harsher methods, would be to get some enamel reducer if you can still purchase it where you live, remove the door latch screw and soak it in a bath of the reducer to see if it will lift the layer. Keep track of how long you soak it, checking in as it soaks, and see if that will work. If so then you can try and address the door data plate
Others may have other or better methods that have been successful with