Saturn 2010 AURA - Manual (Page 351)

{ WARNING:
Rust or dirt on a wheel, or on the parts to which it
is fastened, can make wheel nuts become loose
after time. The wheel could come off and cause
an accident. When changing a wheel, remove any
rust or dirt from places where the wheel attaches
to the vehicle. In an emergency, use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get all the
rust or dirt off. See Changing a Flat Tire on
page 6-74.
10. Remove any rust or dirt
from the wheel bolts,
mounting surfaces
and spare wheel.
11. Install the compact spare tire.
6-81