When I bought my old Starcraft, there were multiple applications of different sealers, from roof tar to RTV silicone. All were applied to stop leaks which were ineffectual. The roof material is aluminum with standing seams.
I used a 4" grinder with wire brush to remove the bulk of the nastiness. I then used mineral spirits followed by lacquer thinner to remove the rest. Along the way, I discovered 3M caulk remover which works great for removing beads of caulk.
After the sealant removal, I installed Eternabond tapes and then sprayed an acrylic roof coating. Everything is still in good shape four years later. I may get up there and spray on an additional coat of acrylic coating as it's easy to do.
Eternabond installation:

Finished roof:
