Clean hands assured

Claude Davis of Melbourne, Florida obtained a patent for this curious device in 2000.

The gadget attached to bathroom doors. Whenever someone turned the handle to open the door, the gadget would spray their hand with dye. This, reasoned Davis, would encourage people to wash their hands, to remove the dye. He imagined his invention might be useful in restaurants and hospitals that have “statutory type hygiene requirements to have their staff and employees clean their hands after using restroom facilities.”