I did replace the caps on my Pentas a year ago. I also used hot glue. I put hot glue approx 5 mm wide and the length of the cap on the board. Let it cool quickly a couple of seconds then pressed the cap into it. It holds very firmly.
More work was to remove the old glue before that. I used a very sharp knive, my Swiss army knive, to gently (without too much pressure, avoid for all sake slipping to not cut yourself or other parts on the board) squeeze the blade between board and glue.