New to Grumman/airplane ownership and developed this problem in my Grumman AA5A in the last couple days. Filled the tanks to slightly over the tabs (the most I had ever filled them up) and while flying noticed blue avgas on the left flap. Took the picture after I cleaned up most of the avgas. I have done a little research, looks like at least part of the inside of the tank will need to be resealed. Looking for advice from other owners who have had this problem and how much it cost to have a mechanic fix it. Thanks for your help!