Q: Mid 2010 iMac : Glass Panel not alined and how to clean panal and glossy display?

after taking apart my imac to upgrade the HDD and re attaching the glass panel back into place there is a small issue, the glass panel  is not alliened with the aluminium and you can see a small space seeing inside the mac on top. there are some marks on the glossy Mac panel also, how do i fix this panel and clean both the glossy panel and glass panel.

Thanks