Sea water intake hose repair

I have a 1996 Bravo 2. Replacing seawater intake hose from outdrive to transom. I have the bell housing off and am trying to remove the water hose from the transom, have removed the fitting on the inside of the boat that attaches to the hose that takes the water to the pump so the end of the intake hose is exposed. There is an insert in the end of the hose that threads in and expands the hose to secure it to the opening in the transom. I have the tool to remove it, which I used to remove the other end from the bell housing. The problem is there is a build up of I assume is salt and minerals from the ocean that has made the opening smaller and constricted so that I can't fit the tool to remove the insert to remove the hose. What are my options to remove it? What can I do or use to remove the build up to fit in the new hose?

New hose, new insert. Just don't dig into the metal when you're demolishing the old. I would first scrape away as much as possible, then spray white vinegar on there and let that work on the marine gunk. a round brush like a bore brush can help. Ultimately, you aren't gonna save the old stuff so...

usually "Bravoitis" hapens at the inside