Large rat proof metal bin (Southern Sunnyvale)

Wanted: Large metal bin that is rat proof. We are collecting empty 35lb dog food bags from a local animal shelter and they will only hold them for us if we provide a large metal bin that they can use to store the empty bags outside. They are also having a rat problem so the bin needs to be rat proof. (I can make it raccoon proof on my own). An old metal trash can is perfect or something similar. Anyone have one they want to get rid of? Let me know. Thanks!