Give the dash a good wipedown with the Water/Woolite mix then retreat it with something like 303. As for UV protection in the products I'll post an interesting quote from Ron Ketcham who appears to know more than a little about some of these products.
Qoute
"303 has a higher resin content, the maximum that can be used, which is why it cost more.
Most of the mass marketed PDMS are usually around 18 to 20%, most professional dressings are between 22 and 27%.
Cost is an issue for professional detailers, and even the higher resin 303 does not last "that" much longer than a, say 24% content.
Just looks better for a couple of days.
The "UV" protectant adverstising is pure bunk, it is not possible to actually put "UV" blockers in these types of resins and if it could be done, the product would have to be marketed at about 3 to 4 times a higher price, as a UV components is very, very expensive.
The claim of "UV" protection comes from the resin barrier created and the additional shine, which reflects the damaging UV's.
The real advantage of using a PDMS is protection from the far more damaging ozone that is present. This protection is only there as long as the product is. "
303, Mequiar's, Eagle One (VW's product is Eagle One), etc these are water borne, Polydimetalsiloxane resin formula's, every last one of them.
The present ArmorAll only differs from many other PDMS dressings, (polydimethalsiloxane) by percentage of the resin mixed into the water that is it's carrier to the surface.
Be it Eagle One, Zanio, Mequiar's, Mother's, etc, all the "white-water based" dressings are PDMS.
Unquote.