I stumbled on your web page from 2012 when searching for Spot-X. I really want to buy more but it seems the maker discontinued.

I learned it was made of juglans regia shell. Have you found a replacement item you could recommend to me?

 

It does appear to be discontinued.  I am not aware of a replacement product but there are DIY methods.

Here is one method I plan to try for my shower doors using lemon juice, vinegar and baking soda. https://youtu.be/saGAHGTSEug