Shower door handle

[Sweetrig]

Purchased a used Montana last year (2014; 295RKD). The shower has a sliding 3-panel door. The metal handle was loose so re-glued it with a marine grade epoxy from the local hardware store. (The handle glues directly to the glass). Unfortunately, the handle fell off again. There is some glue remaining on the door which needs to be cleaned off. Wondering if anyone has recommendation for a solvent and a reliable marine-grade glue.