Sometimes clothes with grease or oil get tossed from the washer into the dryer without noticing. As a result, subsequent loads may be damaged and stained because of the residual grease or oil. According to The Vinegar Institute, vinegar is mostly water and acetic acid. Acetic acid is a weak acid that not only gives vinegar its distinct odor, but also helps remove substances such as oil and grease. It's effective in the dryer.
Pour vinegar and warm water into the spray bottle, and spray the inside of the dryer. Let sit for several minutes.
Wipe the inside of the dryer with a cloth. Pour a small amount of dish detergent in the bowl or bucket, and add water.
Dampen the sponge and wipe down the inside of the dryer to remove any traces of the vinegar smell.
Place several old towels in the dryer and turn the dryer on. Let the dryer run for a complete cycle. Remove the towels, and check for any traces of oil marks or stains.