Quote Originally Posted by Ted Crocker View Post
Thank you. In part, I was just looking through things I already have to see if something could be adapted to a badge. It seems like the circlet would rule out just about all coins or coin-like tokens.
If you were to place a coin in some sort of circular frame, it wouldn't look like the "crest" within a "circlet" that identifies an armiger, so there wouldn't be any sort of heraldic "problem".
Quote Originally Posted by Ted Crocker View Post
The other thought was to put a symbol or depiction of something I am connected to on a disk of the right size. It seems like other members are using all kinds of things for cap badges.
Thanks everybody for your help.
Generally speaking a more-or-less sold disc wouldn't be confused with the circlet. What would cause confusion would be if the disc was open in the centre, with some sort of device in the middle that, to the casual observer, would look like a "crest".

Placing a gold USMC EGA on a red disc (with or without "Sempre Fi" along the edge of the disc) doesn't transgress any heraldic regulation as it obviously isn't a crest. But, if you put the EGA inside a circlet (that is a disc which is open in the centre) then you have created a "look-alike" situation, and that should be avoided.