Why do the mustaches of old people turn yellow under their noses?

In some cases, when a man's facial hair turns white, the particular area becomes a dirty yellowish, brownish, orangeish color. What causes this?

Why do the mustaches of old people turn yellow under their noses?

if they smoke or (gross) when stuff comes from their nose

honestly

my Dad got this way, so we talked him into shaving it off

Why do the mustaches of old people turn yellow under their noses?

Normally it happens if they are smokers.

Why do the mustaches of old people turn yellow under their noses?

it is just there sin or they dont wash very well right there dont forget they are old and forget to wash someplaces

Why do the mustaches of old people turn yellow under their noses?

is the answer not obvious????

Why do the mustaches of old people turn yellow under their noses?

IDK AND BUGGERS