Firefox has a setting to dump cookies on exit, which I use.

And there's Firefox Klar on Android. It forgets everything on exit. Some people call it a porn browser, but I've gotten used to it for general use when I don't need to log in somewhere.

	▲	prmoustache 3 hours ago \| parent [-]
		For those that wonder, Klar is Firefox Focus with telemtry disabled by default. It is available on german speaking countries due to trademark avoidance with the Focus magazine.