chances are the trash can wont be food grade plastic, but thats fine people have been using trash cans for a long time as mixing stations.
the key is to make sure you clean it well enough that it no longer smells like plastic inside the trash can when your done. the plastic smell is from plasticines, which are used to make the plastic flexible, being offgassed. this is also what causes the new car smell weird huh, but if you clean it really well and fill it with water for about a week then drain it you should be ok to start using it.