By Gail Marsh
You love your RV, but what are those terrible dark streaks? More importantly, how can you remove them? If you discover dark streaks on your RV, these tips are for you!
How did this happen?
Many RVers are bewildered. Just what causes those dark streaks, anyway? One potential cause comes from natural elements. When it rains, dirt, dust, mold, and pollutants from your RV’s roof wash down onto the side panels, often leaving behind a nasty, dark streak. If left unattended for a while, the streak becomes very difficult to remove.
Another cause of the dreaded dark streak may be man-made. A friend of ours noticed that the previous owner of his RV installed new seals on the slide-outs. Not waiting for the adhesive to fully cure, the guy retracted the slides. This caused adhesive contamination on the sides of the slide.
What to do?
First, determine what caused the dark streaks on your RV in the first place. If water from the roof is the cause, you may find a simple, yet effective and economical cleaner at Dollar Tree. Yes, there are many RV-specific cleaners on the market, but watch the video below and see for yourself. This inexpensive cleaner is very impressive and effective!

If the dark streaks are due to adhesive, don’t despair. Our friend used numerous cleaners in an attempt to clean the dark streaks (rubbing alcohol, etc.), to no avail. Finally, WD-40 did the trick. It removes the dark streaks just like it works to dissolve residue from masking, electrical, and duct tape. Applying the WD-40 on the surface of the entire slide ensured consistency. The cleaning process was then followed up using Sprayway Glass Cleaner. (Dawn dish detergent and warm water also works to remove the WD-40.)
Note: Always test any cleaning agent in an unobtrusive spot, to make sure it’s safe for your RV’s surface.
RV dark streak prevention
Unless you wash your RV frequently or store it inside where it’s protected from the weather, you’ll most likely have dark streaks on your rig. What’s more, the longer you allow those dark streaks to stay on your RV, the more difficult it will be to remove them!
So, wash your rig frequently. Watch for streaks and remove them ASAP. When reapplying seals, allow adequate time for the seal to fully cure before retracting the slide. Remove any tape residue as soon as you notice it. (We’ve requested that our RV repair shop refrain from taping our name and job number to the RV. Now they tape it to the hitch instead.)
How do you remove those dreaded dark streaks? Tell me in the comments.
RELATED
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- What can I do to restore faded fiberglass and damaged RV decals?
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Be careful using LA’s Totally Awesome, it will remove the paint from an aluminum sided RV.
Thanks for the reminder!
Awesome is only $1.25 at Dollar Tree. I keep 3 of them all the time, one in the house, one in the RV and a spare. Cleans EVERYTHING.
“Simple Green”. A couple days ago, I noticed it is now available in a spray bottle at Menards. Works great – removes oxidation, wax and other stuff too and it is biodegradable. Spray on, wipe and rinse. Always test first!
Thank you for the video and information, Gail! I use various sprays marketed by the Wash Wax All folks. Additionally, I have used paste wax to remove stubborn water marks. Have a great day and safe travels!