Wear a hat or visor, insect repellent and sunscreen.
Wear comfortable, old clothes--you'll probably get dirty.
Take a snack and something to drink.
Wear work or rubber gloves.
Don't go barefoot! Wear closed-toed shoes that you won't mind getting wet.
Be sure children are supervised by an adult.

Watch out for poison ivy, poison oak and snakes.
Avoid injured or strange-acting animals, as they may bite or be infected.
Alert your site coordinator.
Don't touch medical waste, chemical containers or barrels, pesticides or
other dangerous items. Note their locations and tell your site coordinator
to contact the proper authorities.
Watch for nails and sharp edges on debris.

Around water:
Wear a life jacket if you are cleaning by boat.
Don't wade into the water unless you wear a life jacket and know the depth.

It's also a good idea to have a first-aid kit on hand.