[shanice]

This message came from another Spanish site but I am sure the writer would want the information shared with as many as possible.
"It seems that there are thousands, if not millions of forged 50 and 100 euro notes in circulation on CB and possibly throughout Spain.
They are very good; fooled the writer. If you are given a 50 or a 100 euro note in change look out for the following.
1. the darker brown block just above left of the main building on the front of the note should have furrowed vertical stripes. you should run your thumbnail across it from side to side and be able to feel the raised stripes. If it is flat, IT IS A FORGERY.
2. On the forgery, the vertical stripe visible when the note is held up to the light is only a watermark, not a dark embedded metal strip.
3. Again, when held up to the light, on the left (on white background) is a watermark of a Roman-style building with the number 50 (or 100) below it. On the real one, the building is clearly defined, and the number is in bright white. On the forgery, the building is very fuzzy and the number is in brown ink.
In general the forgery is much lighter coloured than the real thing. BE VIGILANT AND DON'T BE FOOLED. Supermarket checkout staff at the writer's supermarket (not sure where he lives) reckoned that they were receiving these duds at a rate of between 10 and 12 a day.