The soft, white vinyl trim moldings
that are used to seal exterior RV windows have a tendency to get dark and dirty
over time. Scrubbing them with traditional cleaners has minimal effect. The
darkness is not dirt, but a mold that can actually penetrate the molding.
Here is a cleaning method that has worked extremely well for me...
The moldings can be easily removed if you grasp an end with needlenose pliers
and pull lightly. As a trial, remove just one section. Note that the ends might
have a dab of silicone caulking on them to keep them in place and to seal
joints between vinyl sections. The molding also fits into a groove. Before you
go any further, try to press it back in position to make sure that you can
confidently replace the moldings once they are clean.
Take your molding section and completely submerge it in a bucket with a
water-bleach mixture (approx. 1 to 2 cups of bleach to 1 gallon of water). You
will start to have some good results in a few hours, but it is best to let
everything sit overnight. A light final scrubbing with a soapy scotchbrite pad
may be desirable to remove remaining residues. The results can be astounding,
from dirty black to sparkling white.
Rinse your molding in clear water and press it correctly back into position.
Don't forget the dab of silicone caulk at each end.
If you are ready to tackle the other moldings, make sure you have a plan. It is
very easy to forget which sections go where. Make detailed sketches or take
digital pictures ahead of time. If you have two windows with exactly the same
moldings, you can clean one set and use the other as a guide at reinstallation
time.
An alternative method is to use a Clorox Bleach Pen.
Apply to the affected areas according to directions, but leave on for several
hours before scrubbing and rinsing with clear water. The bleach-pen method is
not as thorough as the soaking method, and several applications might be
necessary to get great results. It is best used for spot cleaning. The
advantage is that the moldings do not need to be removed from their grooves.