[bumbuls6]

as far as Firefox is the best browser for SE, but whenever I open a new window or private window it does not clear the cache and cookies. if I log in to let's say amazon and open a new window or private, the same login is on the new window.
is there any fix to make a new window clear the cache?

it should look like this: https://prnt.sc/EYggPn1K1T-2

[kreecub]

not sure about this because i use a mix of browsers but i think your firefox is on the always private mode in history settings
ie delete on closing the browser,
Ig change it to the normal mode and try again

[Ashgrey68]

sure about this because i use a mix of browsers but i think your firefox i but i cant be done usually