There are a few ways to find burrs in metal. First make a visual inspection. A magnifying device like an
optivisor is ideal. A hand held magnifying glass will work fine, too. Tiny, picky little burrs might require a ten power jeweler's loupe to see them. If a visual inspection does not reveal the problem the next thing to try is a tactile examination. Run your finger over the suspected problem area. Bridges are tough because the groove can be too small to get a finger in. It is also compounded by the fact that bass players tend to have callouses on their fingers. If this is the case, a fine piece of cloth like silk or nylon will snag and show the way. If none of these methods work, and you still suspect a burr is the problem, light filing with a fine needle file followed by a good polishing on a wheel or with a Dremel tool will usually take care of any problems.
Good luck.
