Costumes are traditional for mystery parties and we always urge our guests to dress (in a full costume or in part) as their assigned character. Even so, expect that some guests will likely not participate, either because they didn’t plan anything or costumes aren’t their thing. Either way is fine; we just want our guests to come and have fun. But we do like to have on hand a simple accoutrement to offer to such guests (a hat or appropriate prop) when they arrive at the party. We encourage costuming by announcing in advance that a small prize (like a bottle of wine) will be awarded to the best costume, as decided by the guests.
Urge your guests to look for costume elements at thrift stores, internet sites, yard sales, etc. If you wish to be particularly helpful to your guests, you could include in the initial invite a couple of costume ideas for their character. A couple of signature pieces can easily make a costume – e.g., a hat and camera; a piece of costume jewelry and vintage purse added to a dress; a badge and an officer’s hat.
