My plan B - since plan A didnt seem to meet much approval - would be , decap them in your loading press. At least , being Hornet , they should all be boxer primed so no issues popping the primers out and discarding.
Not sure on dropping them in the ocean - the sea isnt a dump for all to use. Drop them in an offal hole or soak in acetone then discard in your usual rubbish disposal.
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