I would like to have a "blank canvas" to start over with.
Answer: If you want to clean your full settings, you can do a factory reset on the radio.
Go to menu---Local Set---Factory reset.
After reset the codeplug, the ham contacts also there on the radio. How to erase the ham contacts now? As we all known, you have a csv file which contains all the ham contacts. you can copy a csv file, and then empty the contacts but leave one line there. and then import to your radio. and write to the radio. this maybe not the perfect solution, because there is also 1 or 2 contacts there.
another solution,if you want to get a "no contacts" message when check ham contacts. then you can follow below operation. import all the contacts in the software, and write to the radio. but cut the connection during the progress. it wont write any contacts into the radio.