This has been a hassle for me for a long time.
You need a laser printer.
Attachment 6601
Then you make your design and print it on normal copy paper.
Attachment 6602
Then you sand down the metal and cut your design out.
Attachment 6603
Then you put it face down on the metal and wet it with a cloth and lacquer thinners.
Attachment 6604
Done, and it does not rub off.
For a more detailed description, check out my latest blog post.