OK I contacted Garmin and this is the email I received:
Thank you for contacting Garmin International.
"I'm sorry, but I'm not aware of a way to clear these without master clearing your entire phone. You could install an alternative keyboard to get around it, some may be available on the application market while others could be found online. I cannot recommend any of these specifically but that may be something to look into. Please reply to this email if you have any additional questions."
So I downloaded and installed Smart Keyboard. This app kicks butt. The keys are spaced a bit apart so no more fat fingering keys. And you can modify the dictionary. There are many more settings also.
If you haven't tried this app you should.