This is what I found...and this combination works for me:
In Win 10, go to Internet Options -- either via Control Panel or Cortana, and delete browsing history and temporary files, remember to tick "delete browsing history on exit" under Browsing history. Then run CCleaner and Edge will be cleared without skipping any files.
Go to Settings -> Privacy -> Background Apps and Turn Microsoft Edge off and reboot. I did so and now CCleaner removes temp files that Edge uses, and kills the running process that CCleaner doesn't stop and thus, skips.
Open CCleaner and run it. After it finishes and you see the skipped items.... Click on Options Click on Cookies It will tell you something is open and do you want to force a close? Say yes Go back and run the cleaner again and it won't skip it.