All that being said, on to...
Applesauce Brown sugar
Pour your crock pot nearly full of applesauce. Add some brown sugar - I usually start with 1c. and then add more later if I think it needs a little more sweetener. Add your spices - start with about 2tsp. cinnamon and 1/2tsp each of the other spices. Then turn your crock pot on low. Some books or web sites suggest letting the lid rest on wooden spoons in order to allow the steam to escape, but I just put a splatter guard over the top instead. I find the moisture evaporates even quicker that way. You'll cook this down about half and then add more apple sauce. When it has cooked down about a third more you can taste it and see if you think it needs anymore sugar or spices. Keep adjusting things and cooking until you're satisfied with the taste and thickness. I like mine very thick, so I cook it down a lot. If you like it runnier, you just don't cook it as long, or if it already thickened too much you could add more applesauce or apple juice. It usually takes most of a day for it to cook down completely. You'll want to stir it on occasions as most crock pots have a hot spot or two that will tend to burn during very long cooking. In addition to that, you'll want to scrape down the sides as it cooks to keep them clean so there won't be any residue to burn. This may sound like a lot of work but it's not really - and it certainly beats the stove top method that requires constant stirring. After that, all you have to do is can it. Prepare your jars, rings, and lids and let the water in your canner get hot. Fill the jars and process in the water bath, after it comes to a full boil; 5 min for pint or half pint, or 10 min. for quart. Personally, I like the little 4oz. jars and I process them 5 min. If you're not familiar with canning, please look it up - these are not detailed instructions and are only helpful if you're already familiar with all the other necessary steps.
Some of the apple butter we canned in 2009 (the small, dark jars) - I didn't have as many 4oz jars then. I made sure I had plenty of them last year.
Sometimes I make apple juice for apple jelly by cooking peeled, cored apple slices and allowing them to drain in a jelly bag. When I do it that way, I use the leftover apple pulp(pureed with a stick blender) for my apple butter. There's no sense in letting it go to waste and a bonus is that it doesn't take as long to cook it down since quite a bit of the moisture has already been removed from it.