The sink cleaner is that type of everyday inventions we all make now and then, because we simple need something and need makes us creative.
I made a sink cleaner for our kitchen in 1979 simply because I needed one. I considered it ridiculus to use a lot of paper to clean the sink, which was the common approach. We used the one I built until the middle of the 80ies when they finally arrived onto the market (patented design by someone ...). Nowadays they are found in almost every home, just because it is a smart an simple solution to a simple problem.
The sink cleaner on the picture is not the one I made, this one I bought in our grocery store. The original was built from a piece of a plastic bucket and the handle from a broken oar.