Is it OK to re use a wedding ring in your next wedding?

There's nothing "magical" or even particularly "spiritual" about wedding rings; they're just symbolic. It's okay if you and your new spouse are okay with it. Nobody else needs to know; if anyone notices the ring doesn't look new you can always say it's an heirloom (it's difficult for me to imagine anyone paying that much attention to someone else's wedding ring unless their attention is specifically directed to it ... a friend of mine has a titanium wedding band, which I know because he likes to take it off and fling it down hard at the driveway to make it bounce ... but I'm a guy; girls may notice such things more).