Deleting 'Junk' & 'Trash' Folders on iCloud

I just received a email from Apple that my iCloud account (5 GB) is nearly full, with dire consequences. I do not wish to purchase additional storage. I'd like to empty or delete my 'junk' and 'trash' files from iCloud, but can't figure out how to do it. Any clear, concise directions on what to do? Thanks! MLP - Shawnee KS