Perhaps I'm being especially dense here, but it seems to me that cotton, being a natural product, once washed enough to free it of any sizing, chemicals, herbicides, etc., would be considered "organic" or "green" or whichever term under which it would fall. Fact is, there's nothing left but pure cotton.
EXCEPT - what about dyes? Unless done with tea, beets, etc., would they not be considered other-than truly organic? Aren't most dyes from some kind of chemical process?
If green is recycling, then I would suggest the most totally pure way is to give a product of completely washed and rewashed UNbleached (bleach is a chemical) muslin.
Perhaps where this is going is absolutely nowhere and while you are to be blessed for being so considerate of their preferences, you might be better off to ask them before investing money, time and emotion only to find that your gift did not measure up to their standards.
I appreciate caring for our earth, recycling, etc., but IMNSHO, it sometimes gets carried to the point of pure silliness. Yet, to each his own. Why don't you just ask them?