Smart ways to clean a greasy metal vessel?
The secret to getting meat loaf off is to first soak it in cold water for a good 15 minutes or longer. Cold water soaks are good for high protein food like eggs and meat as well as starches like oatmeal. On a scratch-able surface I like to use a butter knife to gently pry off the material that doesn't wipe off after a soak. Fingernails work too if yours are long enough. Then a gentle rub with a plastic scouring pad, not metal. You just have to keep at it. 

This is why I use non-stick, ceramic or glass for meat loaf! It isn't glue, but it's close.