eh maybe not... time to put this one to bed
To Use after a Private Mailbox - Two Us after P.O. box --> POW
anyway, tying into the rest of Celebration Conflagration
the second part was a cryptogram that said the key to the third was at the end of the first.... and if you take the ENDs of the PoW answers you get ERATOSTHENES
and then using a little thing we math geeks like to call the Sieve of Eratosthenes (which is used to find prime numbers), you substitute numbers for words and sieve out all the non-prime to leave you with a clue that basically tells you that you just wasted your time and to go back and do it again but this time take out the primes and leave the rest....
which would have led to the final riddle to which the answer was: ABLIGURITION, or excessive spending on food and drink, going along with the celebration theme.....
however, EDM decided to tackle the last parts first and found the last riddle before the PoWs ever had a chance to take off, so i decided to split them off into their own little world so they would be easier to keep track of with all the other guesses flying around for the final riddle....and there were a lot of those to clean up
which brings us here, solving the first part of the party after the last three have been dead for weeks , will plan better next time i have a multiple part riddle