Sorry to be clear: "If I wipe and do a sync on a phone, my phone's bookmarks stay polluted" should have read: "If I perform a wipe from the PC with the 'good' boomarks set, when its over (and the server's bookmarks set reports correctly), I do (or wait for) a sync on a phone, that phone's bookmarks stay polluted"

It seems like an incorrect design if "Desktop bookmarks" on a phone can overwrite the desktop bookmarks in the Sync cloud from the actual desktop versions of Firefox.

On the phone, if you disconnect from Sync, can you make mobile Firefox forget about the Desktop bookmarks or does it retain those?

thanks for this, I certainly see your point, once again performed a successful wipe yesterday to the server. Since then have only used two PCs browsers, both had good sets of data. Phones still have bad sets. This morning disconnected then reconnected a phone from sync, still had polluted data after the reconnect. This afternoon my main PC got repolluted again, so I strongly suspect the phones are the cause of this, as the only other possibilities I see are the server or my main PC spontaneously deciding to revert to a previous bookmarks set, which seem unlikely. So I think I'm still asking if there's a way to stop the re-pollution from the phones without having to totally uninstall and reinstall firefox on them both?

I see that you can delete individual bookmarks and folders under Desktop Bookmarks on mobile and this eventually spreads to the other devices, but that would take a long a time. Did you already try deleting them on the desktop side first? I would do a couple dozen at a time and allow for sync to the phones and see whether that works better than clearing from the cloud.

thanks for this, sadly with 14K bookmarks and 2+ years of reorganisation between the bad and good sync, any thought of manual intervention is what i'm trying to avoid! 4 days after my last wipe from the good PC, the repolluted bookmarks came right back to it. I uninstalled FF on my phones, disconnected them from sync, re-wiped good bookmarks from my primary PC again (I find I have to use what I call 'Mark's trick' here, as I couldn't seem to perform a wipe before getting repolluted, instead I had to do this: turn bookmark sync off on the PC, restore good bookmarks on it from bookmarks UI, then do a sync - that's Marks trick: it wipes the server bookmarks - then turn bookmarks sync back on and sync again, at which point you can access bookmarks in about:sync to do a 'wipe' on server-actions (which has seemed to work well for me to stop all other PCs getting repolluted, which is great!!!)

Its only at that point I re-enabled sync on the phones. So: It would be useful if you could do a wipe in an easier way, and if phones would respect it

(It would, of course, also be useful if I had a better way to clear up my old bookmarks ;-)). I'll mark this as solved if I get through a week without the bad bookmarks coming back.....