It might, but I do not know for sure.  Our Westy is parked under trees so gets a lot of oak and some pine residue on it and that requires an energetic scrubbing first, utilizing sponge, scrub brush and Scotchbrite pad. Once that's done and rinsed it's okay to proceed with the Penetrol.  Even if the discoloration is not completely removed, it's likely to be on the topmost part of the roof and you can only see the sides of the poptop from the ground unless you're over seven feet tall. Not a problem for most of us.
Stephen 

    On Friday, July 21, 2017 12:48 AM, Jeff Palmer <w.jeff.palmer@icloud.com> wrote:
 

 Hi Stephen.  Would this work to cover discolouration caused by tree sap?

Thanks
Jeff

> On Jul 19, 2017, at 3:15 AM, Stephen Grisanti <bike2vcu@YAHOO.COM> wrote:
> 
> Penetrol works to restore the finish of a chalked Westy top.  I use it on mine every couple of years. Would it try for your project?
> Stephen 
> 
>    On Tuesday, July 18, 2017 8:54 PM, Alistair Bell <albell@SHAW.CA> wrote:
> 
> 
> Bit of a back story. The original face plate on the sink unit in my van, and the indicator light panel, were really ratty with creeping rust. So some years ago I sanded and painted them with the only paint I had in hand, satin black. Sure it had a rat rod look to it, but when I bought a used kitchen unit a few months ago I swapped in the main panel. It's in fairly good condition, but a little faded and i think more matte than it was originally.
> 
> It didn't come with the indicator light panel so today I painted my black one ( and I actually sand blasted it first) Krylon espresso brown. It looks good but it's not a close match to main panel. It's deeper in colour and it's glossier. It's much closer to the vinyl trim colour.
> 
> I wonder, am I right in assuming the stock brown fades and chalks a little with age? And has anyone found a treatment short of a re-spray that restores the colour to some degree? 
> 
> Thanks 
> 
> Alistair 
> 
>