Unfortunately, far too many digest magazines come with mailing labels attached. For collectors, they’re unsightly intact or stripped off like the pitiful copy of EQMM shown here.
Dealers will sometimes use a product like Super Safe® Stamp Lift Fluid and carefully remove them. If you’re buying on eBay, look at the pictures carefully. The Lift Fluid does a good job, but it can’t remove every trace of the adhesive. If you look closely you’ll see two strips where it was, with a light stain that bleeds through to the inside front cover as well.
Between the label or a trace of adhesive, I much prefer the trace. The fluid does not seems to leave any discoloration where it was applied, however, I don’t know if this remains true after a few years have passed. Time will tell.