I just redid some seams on my MH and used a bath tube sealant remover tool from H-D also a thin screwdriver to get down into seam to get loose sealant. I purchased some Marine Silicone Sealant at West Marine in tube that was very easy to work with and you can dress the seam with your little finger to give a finished-pro look.
I used white but comes in other colors The tube was tuff to squeeze for a small 1/4" bead would use a gun tube next time.