new to trailers and Replacing very old roof seam sealant

[ralph01]

I am new to travel trailers and have a used older 20 foot trailer. I am in the process of replacing all the old seam/vent sealer on the roof, which I think has never been replaced and is over 12 years old. Anyway I and taking one section at a time due to my schedule and am presently removing the old sealer from the front edge of the roof (where the hitch is) where the rubber meets the vinyl or plastic siding.

I have removed about 70% of the sealant very carefully with a putty knife on warm days when the sealant is softer.

Now how clean do I have to have it to use Dicor self-leveling sealant, both the rubber roof portion and the vinyl?

I will take off as much as possible with the putty knife but then do I use a very stiff brush with detergent or mineral oil or something else to get it down to the rubber and the vinyl???? and how do I keep whatever I use and/or the water from getting into the crack?

I do know if mineral oil is used I cannot get any of it on the rubber side of the roof, which brings up another question what do I do around the vents as they are situated on the rubber portion of the roof.

[Nut4speed]

Dicor has some good videos on their website.

[1bigmess]

Mineral spirits is what I have heard for cleaning.