Sea glow and then seal
When I used to do boat shows at Oakland, I used to give tiny amounts of Sglow to people to go back to their marina (close by) and try on discolored lifelines. They always came back and bought!The the discoloration is of two types. This applied to dorade vent (especially) and also to fenders (particularly the tops) and to older vinyl inflatables from quicksilver, west marine/zodiac inflatbles. ALso applies to Hunter rub-rails At least the brown surface part).The surface brownish color is due to exudation of plasticizer that forms a brown gum that then dries into a brown "varnish" (or blackish if there is much ari pollution). Ideally it should be dissolved off without dissolving (hence damagine) the vinl too (as with acetone). IG SG SELECTIVELY dissolves off this brown crud plus any oxidized viyl. You will notice this happening in a few minues as thesurface getst sticky and you will see the brown coming off on the paper towel (you can use paper towel although, initially light scuffing will help if the surface is really bad).Underneath the surface brown, white vinyl becomes yellowed, partly thorugh the presence of oxidation and (mainly) just becuase all older plastics get a yellowish look (even applied to human tissues!).Sea glow has a conditioner that soaks into the vinyl (which is surprisingly absorbent) putting back lost plasticizer anti-oxidants, mildew infhibors etc but (more dramatically impregnates with a special fluorescing agents that, in the presence of UV from sunlight makes the plastic snowy white again. This is easily demonstrated by dribbling some onto an old fender in daylight andjust watching as it turns white!After cleaning the surface, just neutralise (wipe with a little water) and then seal the surface. We used to think that just wateroproofing the surface with a wax or armorall etc was OK but this proved not to be so. You actually need to replace a physical "skin" on the surface of the plastic. Silkenseal does this (becuase it has a cross linker) but even better is final glossy coat of Superglaze.Now to the other products. If you are just doing a small job like lifelines, white wall tire cleaner is fine (I have been told). SInce it has some petroleum solvent it will dissolve off the brown film but has none of the other advantages of Sea Glwo (preservation, fluorescing agent - cannot be used on other surfaces including gelcoat etc.Oxiclean or ANY water based cleaner cannot penetrate the hardened gum and is only good for surface dirt. The "bleaching" and stain-removal properties of oxiclean and related products is due to their generation of hydrogen peroxide and peresence/generation of Sodium hydrogide ("caustic" that is a good grease cutter that acts by saponification.- but being water based they cannot penetrate the plastic.Might be very good for some other surfaces etc like canvas etc.Hope this is not too boring!. The online instruction book has more (top of this site).ThanksJim W