Damn Skunk!
 

Barry wrote:

For whatever reason, last night a skunk decided to let fly against a
four or five square foot section of the white vinyl siding. A weak
solution of bleach water neutralized the odor in pretty short order, but
all attempts remove the yellow stain have failed so far.


I have no experience dealing with stains like that so this is nothing
more than a guess. What you need may be some kind of enzyme that can
break down biological stains. Call a pet store and see if they have
something for your problem.

Damn Skunk!
 

Barry wrote:
For whatever reason, last night a skunk decided to let fly against a
four or five square foot section of the white vinyl siding. A weak
solution of bleach water neutralized the odor in pretty short order, but
all attempts remove the yellow stain have failed so far.

Use straight bleach, wipe it on and leave it.
Give it a few hours.

I don't know for sure that this will work,
but I have cleaned white gutters with bleach.
Often they don't look clean until the next day.