There is a lot of information about the Euro banknotes but the most important is: It is perfectly save to wash Euro banknotes in the washing machine*. They get clean and are fit for use next time you go shopping. Alternatively, one could try and remember emptying all jeans pockets before washing.
Washed banknotes: 5, 10, 20 and 50€ (not all at once – this post reflects years of experience)
Washing programme: 30°C, 40°C, Colour and white