Do these clamps come with tightening bolts and hardware?

No, the set includes the band clamps only. You'll need to source bolts and fasteners separately—most builders use stainless steel hardware to match the clamp material and resist corrosion.

Can I reuse these clamps if I remove them once?

Yes. As long as you don't over-tighten during removal and the band doesn't warp, you can loosen, remove, and reinstall them multiple times without losing clamping strength.

Do I need to prep or clean the exhaust pipe before clamping?

Light cleaning helps—remove any loose rust, dirt, or scale from the pipe surface so the clamp seats flat. A wire brush or cloth is enough; you don't need to sand or prime the tubing itself.