I need help.
 

I have been hand embroidering on the butterfly quilt blocks for all most a year. Finally got done and when I went to look at all my blocks. One of the first ones I did has a yellow stain on it. Now none of the others have a stain. Just that one. How can I remove the stain? It looks like some one peed on it. It don't smell, not greasy, about the size of a half dollar. I am just livid. What can I do?

Is it possible it's a droplet of coffee or tea?

maybe try a little peroxide

I would try to keep anything you use away from the embroidery thread, if possible. A lot of embroidery thread is not very colorfast. If you think the stain is organic, then some Oxyclean should help. If that doesn't work, I would try peroxide. In any case, I would protect the embroidery from the things you try by covering it up and perhaps using a cotton swab to dab the cleaners on.

if the floss is colorfast, you might try soaking in non-chlorine bleach solution.

What I would try, first - Lay the block on a white washcloth or towel, then just blot with a wet/baby wipe (use the plain ones, NOT the ones with lotion). Don't rub; just keep blotting. Change the cloth/towel, when it gets too wet. Try not to wet the embroidery thread, if possible.

Believe it or not, wet/baby wipes will safely remove many stains!

I agree, love me sum baby wipes!

I keep a jar of Orvus soap in the house, you can find it in quilt shop, it takes yellow spots away and doesn't damage the fabric at all, it works wonder on my antique linens and laces. One jar will last you a very long time!

Shout also puts out a wipe. It works on coffee spills, etc. when I spill on my shirt. (I've become such a slob as I age.)

I have a bottle of Pencil Mark Remover from Quilter's Rule. I have used it to remove all kinds of stains. You just spray it on and let it dry. If the stain is fainter, but still visible, spray again. It is worth a try. Good luck.