As with Action Scuba, we are a 100% AWARE dive store, during dive #4 of the PADI Search & Recovery specialty I always bring my students to pick up trash as part of the performance requirements.

Instead of having them perform a search pattern in order to recover different object I would have hiden, I ask them to perform a search pattern in order to clean an area of the dive site. To complete the performance requirements, there's always something big enough to use the lift bag!

We recovered around 40 lbs of debris including numerous beer cans and a bicycle.