Selling for the RECYCLING OF THE REELS themselves, although buyer could test the tape before removing from the reels just in case they're feeling lucky! However, be aware they will probably be sheddy so test at your own risk!
In order to reuse the empty reels, buyer can unscrew the reel and remove the tape pancakes.
To buy an empty reel of this size brand new costs £50-60
https://www.thomann.de/gb/atr_magnetics_master_tape_1_4_empty_reel.htm