US Mail questions (what remains?)

When you consult the US Postal Service (via their web site) prior to mailing a letter, these are the first questions they ask you: What are you Sending?  Cremated Remains – Learn about mailing Cremated Remains  Live Animal(s) other than Day-Old Poultry – Learn about mailing Live Animals  Day-Old Poultry – Learn about mailing Day Old Poultry