I have a cheap Mountain Bell corded phone. I can't figure out how to clear the Caller ID history. No longer have the manual. It has the following buttons: up, down, call back, delete. I've tried holding down either button and pushing one either once or twice to see if it would work.

If you know the model number you might be able to do a search on the internet to find the manual. Otherwise you could call the repair line for your provider and ask them for help.

I'm sure you bought up CID log and tried to press delete, or press and hold delete.