Unfortunately for those of us who prefer to etch a few proto boards at home when possible to test out a basic design & build quick development boards, stencils generally cost $35 or more and take a few days to get back. This is a way, using the same tools as etching circuit boards, to build quick proto solder stencils. The quality probably won't live up to the stainless steel or mylar ones you'd buy, but you might be surprised.
Note that the same method can also be used to chemically mill other designs -- decorative pieces for jewelry boxes, shadow designs for projecting with a Luxeon, etc -- possibilities are endless.
This method as posted won't eliminate the cleanup work, and I'm sure there are refinements to this method that will make it all work that much easier/better. I look forward to comments from others on ways to improve the method.
Apologies for lack of pictures in the later part; to get the pictures here I did a quick run-through but didn't do the actual etch/solder paste application. Poor quality pictures are due to close shots with a cell phone camera.