i would bleach the spot as long as your not worried about color change. 1 part bleach to 9 parts water, spray it and let it sit for about 3 min tops and rinse it well. then re apply a sealant. its not gonna hurt the fabric unless you leave it on there for a reallly long time. just think how long your white t's last. i have white tees ive washed 200 times with bleach and the fabric is fine.