Try your local friendly upholstery shop. Junk yards ?? Last resort - the Toyota dealer.

I honestly think that the only cars available these days 100% rust proof are the new German cars that go through a rust proofing dip before being painted. So it gets all the internal chambers. Otherwise... for every other car it's just part of the painting process. So many cars get scraped on the rockers and subframe that paint will come off and rust will still happen. My 91 Toyota Supra I am restoring had no undercoating and I am so lucky that it has not rusted underneath over the past 20 years. First thing I did when I got it home was take off the exhaust and drive shaft, removed the engine and transmission, put the car on a rotisserie, and I ground off all the paint on the underbody and frame. I then used por-15 rust proofing on the whole underbody, inside the subframe,in the wheel wells, and bottom part of the firewall were you can't see behind the motor. I then applied a good primer on top of the POR-15 I reapplied new seam sealer over all the joints. I then towed the car to the local line-x shop and had them spray the entire underside of the car, and in the wheel wells. It has a nice smooth finish. Is way more durable than any rubberized undercoating and works as an excelent external sound deadner. And they didn't charge much because I had the car stripped down on a rotisserie. So it made their job very easy. Once I put the car back together I took it for a drive with no interior carpet or trim and just the line x made my car a lot quieter especially at hwy speeds.

search "undercoating". there are several, might be 1 that's recommended for your region.

We have a new home build that Is almost completed. My concern is keeping the light gray carpeted stairs clean As we have two dachshunds #shortlegs and their belly’s will rub up and down those stairs all day long. I have seen clear plastic stair treads but wondering how those would work out. Or even a clear plastic runner but wonder how that would stay put. Any advice greatly appreciated.