You can try to re-boot and do the clean up in safe mode. I find it hard to believe it’s all temp data though. Check you internet settings, you may want to purge them every time you close the browser. This way you wont have to worry going forward.
Click on the gear icon > Internet Options
Go to the Advanced Tab.
Scroll to the Security section.
Tick the Empty Temporary Internet Files folder when browser is closed checkbox and click apply.
There may be similar setting depending on what browser you are using.IF you need info on another browser let us know.