ESPHome - reuse board and clean up config

I often use my boards first to experiment with various configs before I commit to the final setup. So I will create device in ESPHome, configure it and when I’m done I will delete it from both ESPHome and HA. But then when I re-use that board and add it to ESPHome as a completely new device, the HA ESPHome integration seems to remember all the previous devices so that new device will be nested in HA under the previous name?
Is there a proper/clean way of reusing previously used boards ?

Yes. Whenever you are finished playing with a board, manually remove it:

Settings - Devices & Services - Integrations tab

Under ESPHome select the device to remove, then the ellipsis menu (bottom right) and choose Delete

yep - that is exactly what I’m doing - however when I create a new device re-using that board HA somehow remembers that it was previously used as a different device even thought the encryption keys are different and the ip address is different so I suspect there is a register somewhere where the MAC address is stored or something similar