Trash
Practice low-impact, no trace camping. Leave Monte Blanco cleaner than you found it. Try to be a good role model for the locals who are lets face it hopeless litterbugs & lousy graffiti artists.
Collect trash left by those who have come before you.
If you pack it in, you must pack it out or burn it. As usual, we burned all the trash we could find at the base camp. A Peruvian guide taught us to bring candles to fuel the fire. The perfect burning barrel is a hole in the ground with a candle at the bottom.
Monte Blanco campsite was quite clean when we left it. Except for hundreds of burned tin cans left behind by other large groups. Someone needs to organize a burro to carry them out! Like cleaning up Mount Everest.
Bring thick plastic (string-tied) trash bags. We've even used waterproof stuff sacks to carry out trash. Once emptied of food, they become trash containers. They protect garbage from insects & vermin & are easy to attach to the outside of your pack.
Plan meals which minimise the amount of trash you will need to carry out. For example, package your food in burnable containers.
Grey water should be disposed of at least 30m (yards) away from the campsite. This includes biodegradable soap.
Pack out garbage with plastic or metal content. (e.g. twist-ties, foil, etc.)
Pack-out or burn cigarette butts. (Why dont you go cold turkey this hike)
Pack-out or burn fruit peels, especially orange peels.