Bury it before it starts to smell. I can't imagine being a garbage collector and opening the lid and finding a dead animal in there. It'd be suspicious and creepy..oh and don't forget smelly after being in it for so long.
Or cremate it. It costs money, but a lot of areas won't let people bury their pets. (Which I find incredibly stupid.) With this way, you may have to spend money, but it's for a good cause, and for a good pet. And I'm sorry for your loss.
You need to bury it but anywhere except somewhere that it can be seen due to the fact that it's illegal to bury things on properties that could possibly in the future be owned by another person but if the pet is something small and tiny like a gerbil then it's ok
If it was a dog or cat, many animal hospitals will only charge $25 to bury it. You can also do it in your yard or a Forrest. Wrap it in plastic bags. Do it at least 3-4 feet so no animals dig it up. I'm sorry for your loss.