Not sure how the waters are by you but stuff washing up on the beach around here is probably laced with contaminants from the boating traffic, etc. I don't think the stuff washed up is the best of the best to put into your tank.
That said lots of people around here use NSW
in their tanks taken right from the jetty in the winter at high tide so it is all a matter of personal preference (and willingness to take risks).
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