If there's any accessories (desk brackets, shelves, etc..) then they become more useful. I'm guessing not.
If you have welding/fabrication skills, that opens more possibilities than using them whole or cutting and bolting together sections.
A.) in pairs:
firewood racks
B.) cut down to make workbench legs
C.) cut apart and use the sections to build
whatever...
D.) trade them for ca$h money as scrap metal, buy something you need, maybe chocolate. (haven't sold steel for a while, I have heard some places have a ton minimum load for steel & iron)
D.1) sometimes the scrap dealers have interesting stuff taken as scrap set aside to resell, or trade.
E.) the levelling feet could be reused in a new
project, unscrew them all and save those if nothing else.
E.1) you maybe could Ebay/Craigslist the feet for more money than the frames. (options D & E go well with each other --
save the feet, scrap the frames--, in fact if the feet have plastic, the scrap guy may stiff you for it not being ALL steel)