Best cleaner for outside trash can?

Have you tried mr clean

First check with your city sanitation department or health department. In some places you are not allowed to use certain products because they will be washed into to sewer system and eventually into the water reclamation system. But if that does not prohibit most cleaners, I recommend bleach and water. You can make it up, 1 cup of bleach plus enough water to finish filling up the jug, for cleaning trash cans. You can add a good squirt of dishwashing liquid (Dawn) to help clean off sticky gunk, and the bleach will help sanitize the trash can. The can will be sanitized only if you clean it frequently and thoroughly each time. Both the bleach and Dawn with ammonia will resist water spots, but to avoid them completely, keep a stack of shop cloths or paper towels to dry the water spots each time the can gets wet. You might want to spray the can with Rainex. Best wishes ☺️

http://idreamofclean.net/the-easiest-way-to-clean-out-a-large-outdoor-garbage-can/

The best trick I've found is to use a bit of dishsoap and a garden hose with a good sprayer

Baking soda, vinegar, dish soap, and water are my cleaning friends. You will probably need to leave it soak for a bit if your trash can is really cruddy.

Funny, my were getting really yucky in spite of washing. I just called my trash service, they picked up the old ones and brought me brand new bins!

Sudsy ammonia. Then just spray the hose to rinse.