MacID v1.1+
Unpair your iOS device, quit MacID and then drag MacID to the Trash in your dock.
In Finder, navigate to to the Application Support folder located in the hidden user Library folder and then drag the MacID folder to the Trash. (Open Finder, click Go while holding ALT and the hidden Library folder will appear in the menu.)
Open Keychain Access, type "MacID-Secure-Data" and delete anything that shows in the results.
Empty the Trash and MacID is now removed from your Mac.
MacID v1
Unpair your iOS device, quit MacID and then drag MacID to the Trash in your dock.
In Finder, navigate to to the Application Support folder located in the hidden user Library folder and then drag the MacID folder to the Trash. (Open Finder, click Go while holding ALT and the hidden Library folder will appear in the menu.)
Empty the Trash and MacID is now removed from your Mac.