Scuffing the wiffleball is an art. Some people use sandpaper, cement, fingernails,
rocks and many other things.
Scuffing will increase the amount the ball will curve. I believe
this is because the extra surface area will magnify the effect on the
wind without adding any mass. Imagine, throwing a beachball, (which as
about the same mass as a wiffleball) a little spin will make is curve
quite a bit.
However the scuffing the ball will slow it down. Just as not many
people can throw a beachball very fast (not with out gale force downwind).
Scuffing will also increase any tail that your straight pitch allready
has. So, if you just through straight pitches you should use unscuffed
balls.
Still, some things about scuffing I can't explain. Some wiffleball
have a mind of there own,
