I have always used the ones with glue on them out of the box. Never had to remove them but I believe them come of easy with the use of a hair dryer..
Sikaflex, tigerseal or any PU (polyurethane) sealer is used for that sort of job. Basically it’s windscreen bonder and vehicle structural sealer that nothing melts
Buy cheapest Pu!! No need for branded btw. That was just an example. Once used the rest of the tube won’t keep btw as it starts curing back into the tube faster than silicone