color-changing hand soap?

JenzillaMay06

I could swear that I've seen a hand soap for kids/toddlers that changes color or something, so they know when they've rinsed well - does anyone know what I'm talking about? I was looking for it in the store and couldn't find anything.

Alibabs

Kandoo I think, do this. I remember seeing it written on the bottle about colour changing but I didn't know what they were talking about because it didn't look like it changed colour to me! But perhaps they were talking about something else..anyhoo...I saw this online: https://www.americarx.com/products/23512.html