I found a black grease spot on a quilt top I'm working on for my GD. I don't know how it got there but I need to try and remove it. It's on the white on white background. I tried washing it after putting Stain Stick on it (which usually takes just about anything out) but it didn't all come out. I heard somewhere about using WD40 or Goop Off. Does anyone know if either of these might work? I'm open to suggestions because replacing the block is not an option. It's 21" square and has 6 large butterflies applicaqed on it. Thanks for your help.