Hi Joy!
That's very strange that you are finding these results! I would certainly encourage you to reach out to care@koh.com.au with some more information and we will do our best to help!
Regards,
Sean,
“Using the Koh spray on surfaces and wiping off with cloths works well and doesn’t leave any residue. I used it on our windows and was surprised at the good result. We have an okd shower and not sure it gets all the soap residue off.”