Martha, I did a search and came up with these instructions:

Instructions
Things You'll Need

* 2 white towels
* Color-safe bleach or oxygen bleach containing sodium perborate
* 2 white cloths

1. Place the quilt on a level surface with the brown stains facing upward. Lay a white towel folded in half directly under the stains. Dampen the brown spots with cool water.

* 2. Dampen a clean white cloth with a bleach containing sodium perborate. You can commonly find sodium perborate in color-safe bleaches--such as Clorox 2--or in oxygen bleach. Oxygen bleach comes in a powdered form; mix it at a ratio of 1 cup of oxygen bleach for each gallon of water before submerging the cloth in it.

* 3 Blot the brown stains--do not rub--with the dampened cloth. Start at the outer edge of the stain and blot while moving inward toward the center. Continue blotting until no more liquid can be absorbed.

* 4 Dampen a clean cloth with cool water. Blot the area to remove the bleach from the quilt. Pat the quilt dry with a towel.