i like the resealable japanese type. you don't slide the cover in and out of the sleeve each time you want to play an lp, so cover wear is kept to a minimum. they also do a pretty good job of sealing dust away from the cover and lp. ymmv, but I'd give them a shot.
Best Outer Sleeves for LPs
Is there a recommended type of plastic sleeve to protect valuable record covers from aging, yellowing, etc? I can buy them very inexpensively from the Princeton Record Exchange, but wondered whether they would have the desired effect. I've also seen poypropylene sleeves sold online at Sleeve City. Any recommendations? Thanks very much!