1998 Buick Century Owner's Manual - Page 252

7. Remove any rust or dirt from the wheel bolts, mounting surfaces and spare wheel. A CAUTION: 5. Raise the vehicle by turning the jack handle to the right. Raise the vehicle far enough off the ground for the spare tire to fit under the vehicle. Rust or dirt on the wheel, or on the parts to which it is fastened, can make the wheel nuts become loose after a time. The wheel could come off and cause an accident. When change a you wheel, remove any rust or dirt from the places where the wheel attaches to the vehicle. In an emergency, you can use a cloth or a paper towel to do this; but be sure to use a scraper or wire brush later, if you need to, to get all the rust or dirt off. 6. Remove all wheel nuts and take off the flat tire. 5-32