vertical lines after replacing battery

After replacing my battery I had a dozen or so vertical green lines on my display. Fearing I had gotten glue that i had dissolved to get out the old one i took it apart and cleaned contacts. Put it back together and most were gone. But there was still a cluster to the right of the display. After a year this has reduced to a single line that i've learned to ignore. Not the first battery I've replaced but the hardest to get out (this one was previously replaced by a professional), hence the alcohol to loosen the glue. What's your best guess as to what I did wrong?