Hi Derek:
Very good of you to offer!
There are occasional beach cleanups here; I don’t know that need any permission for such things.
Part of problem might be that various places are pretty much overwhelmed with garbage from the sea. After Typhoon Hagupit last autumn, I saw various places w polystyrene strewn well above the normal tideline; some places more than knee deep in garbage. Might be able to clean at least some of this rubbish away; but shortly, back it oomes when onshore winds blow.
Martin