Today putting quilt layers together I pricked my fingers and blood drops appeared on white section of pattern! Quickly I cut a long piece of mercerized cotton thread, chewed it to get it soaked with my saliva and then dapped blood drops.
They disappeared almost immediately. I learned this trick in the 60;s when I worked in the alteration department in a
small specialty store in Boston. Still works after all these years - sort of like me!