So how does the “free dye pack” work?
Here’s a nice article on that that free dye pack works. I’ve never heard of a bank charging for one, they give them to robbers as lagniappe, as a Cajun might say.
https://science.howstuffworks.com/question671.htm
It explodes, ruining most of the money, and makes the robbers look like smurfs.
CC