Drilled and removed all bad rivets on inboard and outboard ribs. My rivet removal tool would only fit on one rivet on the outboard end, so all others were drilled freehand. Successfuly removed all rivets and cleaned off remaining sealant with MEK.
Note: Protect semi-cured sealant from metal shavings while drilling. I failed to do that on outboard end and tacky sealant is like a magnet for metal shavings. Had to remove sealant from several rivets to clean up the mess.