I found this a little interesting/humorous on the Bank of England website ...
https://www.bankofengland.co.uk/banknotes/damaged-and-contaminated-banknotes"Dye-Stained Banknotes
We work with the cash industry to encourage the use of dye-staining devices in cash boxes. These devices permanently stain banknotes during robberies, so stolen banknotes are much easier to spot.
If you are offered a dye-stained banknote, we advise you to refuse it. This prevents stolen cash from going into circulation, which acts as a deterrent to criminals and stops them profiting from crime."
Do we have this in Canada?
?