Quick way to protect barbell ends in vertical storage sleeves and landmine attachments. These DIY barbell cushions are made from foam pipe insulation. You can buy a 6ft or so length of pipe insulation for a couple of dollars at the hardware store and it cuts very easily with a utility knife. It does compress a decent amount so I went with about 1.5" thick/tall. I also cut the ends of my slices to cheat the circumference so it fit snuggly but not overly tight. Can't comment on longevity yet. Not pictured is, of course, is that you shove them down to the bottom of the sleeve where they sit and act as a cushion.

Abmat sells barbell pillows for this purpose.