WJ,
If you have PB Blaster, give that a shot. It could help with plastic wad residue. I like to let that stuff penetrate overnight. Works well. Just keep it off the wood finish. Brownells sells a separate solvent just for plastic wad residue, but I'm guessing PB and a brush will do as much.
I needed a wheel alignment on an old car one time, but was told by the tire shop that they couldn't do it because the rear adjusters were frozen and it would cost more to replace them than they thought was worthwhile as the misalignment was small. Just rotate the tires more often was their advice. So, we skipped the alignment. The next time it was due for rotation, three days ahead I bent down under the rear bumper and squirted the adjusters with PB. Did it once each day until the appointment. At that time I asked them do an alignment, which they did, without comment. When I picked the care up I spoke to the mechanic and asked if he'd had trouble with the frozen adjusters? He asked, "what frozen adjusters?" Been a PB fan ever since.
I saw no sign of hazmat fees for the Bore Tech products on Midway's site. But I didn't see any there for Butch's Bore Shine, either. It's a toll-free call, so just give them a buzz. I think if someone is hitting you for a hazmat fee for non-hazardous material, they are just doing a liability CYA job that some other company may not. So look in more than one place. Boretech is sold not only by Midway, but by Sinclair International, for sure. Maybe the company web site sells it, too? Someone who has it is likely to send it without the fee.