Out of my collection of pipes, I only have one in the current collection I've bought new. That is, 90 percent of my pipes are estates and of those estates, more than half came to me in pretty rough shape. Magic erases are littlerly one of the best things in my tool box to get those estates up and running quickly and I'll tell you why by giving you the method in which I "restore" (I'm no professional and I wouldn't recommend my method to anyone but it works for me. I'm sure I'm devaluing the pipe in some way with this method but I use my pipes for smoking, not worried about their value or resaleablity)
The first thing I do after a visual inspection is reem a bowl when I get it. Not all the cake, I'll leave about a nickle thickness and then I'll hit up the inside of the bowl with an eraser and scrub it down to about a dime or thinner. It leaves the very thin layer of cake smooth enough but rough enough that I feel like it builds my own cake quicker than when/if I use sandpaper. If the pipe is in otherwise good shape, I'll remove the stem and do a normal cotton ball/alcohol in the bowl and just use the eraser on the rim of the bowl and work on the stem.
If the finish on the pipe is in poor shape (I know some are going to be appalled by this) the whole thing takes an alcohol bath, depending on how long it takes (4-24 hours). I'll change out the alcohol a couple times during that period until I'm satisfied with the color change of the alcohol (i.e, when it's no longer black/dark brown). After stripping the finish/sanatising/cleaning, the whole thing gets a scrub down with a magic eraser. The bowl and the stem, taking extra time around the rim of the bowl. Then I remove the stems, and all my stems take an oxiclean bath (you would be surprised how much more crap comes out of a stem even after a day soak in alcohol). While that is being done, I twirl up a corner of a magic eraser and I hit up the mortis. Often this is where I get frustrated because they tend to rip and get stuck, but the amount of crap that I rub off is worth the effort. After the stems finish their ocxyclean bath, they get another scrub down with a magic eraser to remove all the oxidation that was brought to the surface. The outside of the bowls get another scrub down. Then they rest for a while.
Then, I get some sand paper (2000+ grit) and spend hours sanding the stem and the bowl. Finally, the whole thing gets wiped down with a rag with olive oil. After that, they rest a while to dry out before they get lit up. I tend to like the "bare" finish I get after this method.
I'm always pleased with the results. I have tried not using a magic eraser, like paper towels or sandpaper inside the bowl and within the mortis and cleaning the stems and the magic erasers cut down my work by several hours. I say all that to say they are probably the best thing in my arsenal to get forgotten and unloved estates back into the game. Lol sorry for the long post