Box chain necklaces are constructed of numerous box-shaped links, folded over to complete the chain. On occasion, you may discover a necklace you love -- but it's a couple inches too long for your tastes. If the links are unsoldered, you can remove these links on your own without recruiting the assistance of a skilled jeweler.
Examine the links in the chain closely. Look for the small seam on the link(s) you wish to remove.
Apply a small piece of cellophane tape over the link you need to remove, as well as adjacent ones. This prevents scratches to the necklace components as you manipulate the links with your pliers. It's wise to protect these links in case you wish to increase the length or sell the full-length chain later.
Grasp the link on opposite sides of the seam with your two sets of pliers, one tool in each hand. Carefully bend the link open just enough to slide over the one it's attached to.
Open the link at the other end of the portion you wish to remove. You might be left with up to a few inches of spare links, depending on how much you needed to remove.
Slip the new end links together, reattaching the chain to itself.
Press the links closed. Inspect the seams to ensure they're completely shut.
Slip the necklace on and test for fit. Make further adjustments as necessary.
Box chains featuring extremely small links or thicker stainless steel boxes should be brought to a jeweler.
Take the opportunity to inspect the entire chain, looking for loose, bent or open box links.