Yuck yuck yuck. When the wet sand is soft to-the-step, and I start finding light-weight aluminum, is the moment I leave.
I never even hunt wet sand, unless the sand is going "out" (eroding). Like after storms/swells/wind/tides coincide. I am not into wandering around for recent drops. I just hunt land during those times of year.
An exception may be for super touristy warm water beaches like Hawaii and some So. CA, where thousands of swimmers converge and are actually frolicking in the water. Then perhaps it's a gamble to wade through the incoming aluminum for some recent drops.