Where do they sell clip-on earrings in Portland Oregon?

If you are talking about fine jewelry ( karat gold and fine or sterling silver), just about any reputable jeweler can special order or convert pierced to clip on for you. If you are speaking about costume jewelry, not only do many boutiques carry clip-ons, but many craft stores and jewelry supply companies (firemountain.com) will carry clip-on backings in their findings section so that you can convert the earrings yourself with a good epoxy, some wire, or something similar, depending on the earrings. hope this helps and take care.