Usually, I'll take the pans out and let them cool on the ground. Later that day or the next, I'll usually pour the greasen in a regular garbage bag and then put that bag in a heavy duty trash bag and put it out with the regular trash.
Or, you can do the reverse of that like I did the week before the last contest... I dumped all the grease in a dirt patch next to my garage. Then put the water pans in a heavy duty trash bag to soak with water and soap for easier cleaning. Then I put that bag out with the regular trash and showed up to the contest without my water pans...
Don't do suggestion # 2 !!!!