I don't have the HP-1, but I can offer a potential idea with what I've found with the 536.
Connect the scanner to a computer. Use the computer's Windows Explorer to look at the scanner's files - the scanner shows up as a Removable Drive.
Somewhere in those files there is a folder called Audio. In the 536 there are two sub-folders, inner_rec and user_rec. Opening up the folder(s) will reveal the recorded audio files. I can then use the Windows Explorer to highlight and delete those files I wish to discard.
It's the same in the Home Patrol. Connect the scanner as described above, choosing "Mass Storage", then use Windows Explorer to find the HP-1 among the removable drives listed. Click on the drive.
You'll see a folder labeled HomePatrol.
Click on that to expand it.
Now, you'll see a number of other folders, one of which is labeled 'audio'.
Click on that one to expand it.
You'll see two more folders.
'inner_rec' contains the audio clips from the mst recent transmissions, the one's you'd hear if you selected the replay function.
The other folder, 'user_rec', contains folders with groups of recordings made if you selected to use "record" instead of only the 'replay' option. Those folders are the ones you want to delete. Don't delete the 'user_rec' folder itself, only the time-stamped folders inside it, or the time-stamped audio files within those individual folders.
