I have some of the cardboard holders that were going to get tossed when the school library was redone. I realized that the very deep shelves in my stash closet could hold mags in the back and fabric or baskets in front. Getting to the mags is, of course, a problem, but I don't get them down very often.
Second idea comes from my guild.....we all donated some mags and on the day of our quilt show sold them for 25 cents each. I bought about $5 worth so I didn't advance much in reducing the numbers, but the money went to the guild. Of course, other people did a good job of donating and reducing their piles. I question whether they are really quilters. lol