The old style polish of beeswax, turpentine and linseed oil will blacken with age. Clean it carefully ... Dust it, then use mild soap and water on a soft cloth to remove water-soluble crud. Then shift to mineral spirits and 0000 steel wool, cleaning gently to get the oil-based hand grime and such off. If you have a flaky, scaly finish, that's probably old wax buildup. Remove it with a blend of lacquer thinner and denatured alcohol (I use 50/50). Apply liberally to a small area, let it soften a few moments, then gently rub off the crud with the steel wool. Repeat until clean. Do this outside, with gloves because the fumes are vile and flammable. This picture shows what removing the decades of old polish and wax can do - It went from black to walnut in about an hour.

Pipe clamps are fine -- but for smaller lengths -- the "pistol-style ' bar clamps will probably be fine as well .You probably will want to open up the split a little more than it just lays to get more glue on the bare wood on the inside surface of the split.. Keep pushung more in with your finger tips -- so much till it oozes out the back side -- then use your clamps -- either kind -- but like Linda said -- not too much pressure -- The too much pressure is all too easy to do with pipe claps -- especially 3/4 inch size. If possipbe clamp it so you can see the whole split after clamping so that you can wipe the excess glue oozing out -- crpenters wood glue WILL NOT adhere very well to "finished or oiled surfaces -- but it is still easier to get it off before it hardens. Do not clean with too wet of a rag. Come back after an hour or so to get any that is late in coming out -- do not move your clamps for at least 24 hours-- or you will not have good bonding. Good luck

Check out the local flea markets and antique malls...most will have feed sacks for sale....you can also take a look at repro fabrics, and if too white, tone them down a little with tea. You can also check the same places, plus next to new sort of places like the Salvation Army stores, for women's aprons. Many of those are made of the sort of fabrics you're looking for. I always wash quilts...both old and new...in the machine. It's fine, if you just don't allow them to agitate, which is where the problems come in. I fill the washer with warm water and whatever I'm using to wash with, and lay the quilt on top of the water, allowing it to sink on it's own....and, then soak...before putting it on the rinse cycle, I generally 'agitate' it by hand, just up and down in the washer. Rinse and spin out. If the water looks still dirty, do the whole thing again. I find this, by far, the easiest way to wash a quilt...leaning over the bathtub, etc, is way too hard on the old back, and if you don't allow it to agitate, it'll be fine! (this is also the way I wash skeins of yarn that I've spun, or those that have some sort of addition that weavers like...never a problem if they don't agitate).

Heat and moisture will loosen hide glue so dis-assemble the whole thing,refit/tighten joints and use nothing other than hide glue(including veneer) to re-assemble. Why hide? Because moisture and water will alow joints be separated if needed later on. IDK what to do with finish either,your call. Good luck and post pics when you are done.