You would be taking an unwarranted risk if you washed this quilt in any way prior to its completion. It might not be pleasant to take it apart first. I would think that some of the odor would disappear if you aired it out by spreading it on a plastic drop cloth outside on a warm day. Be sure to cover it with a cloth sheet to protect it from fading from the sun. Only by taking it apart will you know about its inner construction. When you replace the batting and maybe even a different backing the quilt will be stable and will stand up to laundering. There are several products made to remove stains from quilts. I know that some people dry their quilts in a dryer but I prefer to dry them flat. Again I use the plastic drop cloth and lay the quilt flat. You have a treasure. Please don't take chances of ruining it. If you have a quilt museum in your area or know of an appraiser (like at a quilt show) seek out expert opinion.