A: You can build, just from wood if you like, a funnel—shaped air collector or “hood” that will mount behind the buff. Fit it with a hole to fit the large diameter (2.5 inch I think is common) hose on a decent shop-vac. The closer the fit of the funnel to the back of the buff the better, so air is drawn in from right behind the buff, rather than the whole general area. Many commercial units use a rather large hood, and then need a lot of air movement. But if yours is sized close to the buffs you use, and fits up close to the back, you can collect almost all the dust produced. Mount the funnel so it can shift side to side to be centered behind the working area of different buffs, which may not all mount on the motor in exactly the same position. If the collector can be shifted, you make it more versatile without needing to make it too much wider. I’d guess you’d want something about eight inches high at the front, with the front edge cut to a semicircle matching a six inch buff when mounted on the motor, and perhaps two to three inches wide at the front end. With a good shop-vac you should get pretty good suction from that sort of collector. Mount a piece of coarse screening (perhaps ¼ inch openings) in the back so that any jewelry caught by the buff will get stopped at the screen, not pulled into the shop-vac. Then, in the shop-vac itself, use a HEPA filter capable of collecting very fine particles, so they aren’t simply spit back into the air.