Jewelry repairs can cost anywhere from $20 to hundreds of dollars, but there are certain repairs you can perform safely on your own. Three jewelry tasks to try—and three never to try…

DO: Replace opened jump rings. The jump ring is the circle of metal that often connects a necklace or bracelet to its clasp. But once a jump ring has been pulled open, it is more likely to open again. Silver jump rings are particularly hard to keep shut once opened.

Better to buy a replacement jump ring at a craft-supply store such as Michael’s (www.Michaels.com). These often cost less than $1 apiece. You can replace a clasp, too, but those sold at craft stores are gold-plated and won’t match the color of real gold.

Be careful how you open this new jump ring to get it onto your jewelry. Rather than pull the circle of metal open into a letter C—which would make it susceptible to pulling open this way again—gently pull the ring open to the side as you would a key ring when you wish to add a key. (Use small pliers that have no teeth if possible—teeth can leave ugly marks on the metal.)

DO NOT: Solder breaks in jewelry. Precious metals require special solders. Conventional solder won’t bond properly and could contaminate the precious metal, lowering its quality.

DO: Reglue pearls back into their settings. If a pearl comes loose, you can safely reattach it using a standard five-minute two-part epoxy sold online or at hardware stores. Clean any loose residue out of the setting, add a small amount of epoxy with a toothpick, then put the pearl back in place. If epoxy squishes out around the edges of the pearl, you used too much. Remove the pearl, and wipe off the epoxy with a paper towel dipped in rubbing alcohol. Let dry before you try again.

To string pearls: If the string breaks and pearls are not knotted, the string can be replaced using silk thread intended for restringing—other materials will be too weak. If pearls are knotted, restringing is best left to a professional.

DO NOT: Attempt to reglue loose pearls yourself if the small metal post in the setting has broken off. (There usually is a post that fits a hole drilled into the underside of the pearl.) Have a jeweler replace the post. Also, do not attempt to glue any translucent stones. You will see the glue through the stone. A good rule is that if the stone was glued to begin with, it can be reglued.

DO: Inspect gem settings for bent or worn prongs. Damaged prongs can lead to lost gems. Rub jewelry that has prongs across an inconspicuous spot on a fibrous garment such as a wool sweater. Then examine the settings under a magnifying glass. If fibers have become caught under a prong, it might be on the path to becoming loose enough for the gem to escape.

Similarly, if you have jewelry with “channel set” stones—a row of stones set between two walls of metal—examine these walls under a magnifying glass. If the walls seem to bow outward slightly, the gems could be at risk.

DO NOT: Try to fix prongs yourself. Do-it-yourselfers who attempt this tend to reposition prongs in a way that appears tighter but actually leaves them prone to snagging on clothing and bending back suddenly, such as when a hand bearing a ring is pushed into a pocket. That could allow the gem to fall free. Other risks include chipping a corner off a gem or leaving ugly tool marks on the metal. Prong repair—and channel-setting repair—is best left to a jeweler.