Artificial Fingernails (for Cleaning)
In many household situations, fingernails can be quite a handy tool to clean delicate surfaces from "crusty" dirt. It is somewhat surprising that the powers that rule the industry never came up with a proper equivalent: Either, you are supposed to use chemicals (which either don't work that well or are bad for the environment) - or you use a physical tool which will either be to weak (like a sponge) or cause small scratches (like the green side of the sponge, or steel wool.
So I am proposing a cleaning tool that is like fingernails, meaning it is environmental-friendly and has just the right hardness - hard enough for the dirt, but no threat to the surface.
Reward: Free samples.