[SteveC7010]

If you are talking about the caulking used on window, door, compartment, and other installations in the trailer, the manufacturer uses butyl putty tape about an inch wide that is laid on frame of the window or door before it is inserted into the trailer wall. It squeezes out a bit when they tighten up the screws, and will continue to squeeze somewhat over the life of the trailer.

If you need to replace it, plan to remove the window (or door or whatever) and take off all the old putty tape, replacing it with new.

There's a bit of an art to getting the window (door or whatever) out so before I go any further, perhaps you'd give us a better idea of what you want to do.