To rid your RV of musty or bad smells after storage or after being closed up for a few weeks, place activated charcoal in disposable containers throughout your rig. Don’t use charcoal briquettes, which are not effective and are designed for burning not deodorizing. Activated charcoal is a much safer and effective product for deodorizing. You can buy it in many forms (loose, embedded in filters or as part of hanging deodorizers).
Another way to refresh your space is to use fabric softener sheets like you use in a clothes dryer. Placing them in drawers and cabinets will also give off a fresh, clean smell.
If you know where a smell is originating, use vinegar — which is safer than many commercial products — to neutralize the odor. Vinegar is also effective on pet accidents and for carpets. Stir a teaspoon of white vinegar into a pint of water (more vinegar for tougher jobs) and apply with a spray bottle. Blot the cleaned area and allow to air dry. Vinegar is effective as a general cleaner also.
And, of course, open up your RV’s windows and let Mother Nature do her bit to freshen up your wheeled home.