FRiTZ!BOX 7590: new button 'clean' / 'aufraumen' + how to delete all sensors of the replaced old Fritz!Box

I have gotten a new 7590 which replaced my 7490 and therefore I have 2 issues:

#1
How do I get rid of all the old 7490 senors which has gone ?

I had done the transition to the new 7590 via the built in FRiTZ!Box backup and restore routine which had worked flawlessly
That was a surprise, but now I have all the old sensors in my HA that are no longer supported cause the old 7490 has been SOLD already

#2
With the 7590 and its HA integration seems to have come a new function or in particular a new button ( or I might have missed that with the 7490) which is called

“Aufräumen” in german or I assume “cleaning” in english.

I pressed that HA button the last time when the prime or netflix video stream had struggled and hickups for whatever reason and then it worked perfectly.

But what kind of function is that and where can I find that in the genuine Fritz!Box 7590 UI from any browser ?

I could not find such feature.

There are also more buttons called “new connection” or “reboot” but this looks to me like a new feature:

type: vertical-stack
cards:
  - type: entities
    entities:
      - entity: button.fritz_box_7590_aufraumen
        name: Aufräumen
      - entity: button.fritz_box_7590_neu_verbinden
        name: Neu verbinden
  - type: entities
    entities:
      - entity: button.fritz_box_7590_neu_starten
        name: Neu starten

I have checked the forum for both topics and web, but I did not find the answers.

Thanks

UPDATE to the 2 nd point

The function is a service and is called clean.up or so

It is described here as

"Remove all stale devices from Home Assistant. A device is identified as stale when it’s still present on Home Assistant but not on the FRITZ!Box."

But I still do not know how to remove all the old 7490 sensors and the mess that comes along. Right now I have removed the device from my integrations to avoid further more sensors being created or found.

I can not find any 7490 or 7590 related sensors in the tools and state section, also not among the statistic section. Not sure where they are but I bet in case I add the 7590AX all the 7490 mess might reappear pretty soon.

Any suggestions ?

Which sensors do you mean?
Try the integration „AVM FRITZ!BOX Tools“ and you should see all entities of your FRITZ!Box.