Summarize this article in one sentence.
If you have stains on the outside of your Ugg slippers, try using a large eraser to clean them. Simply use the eraser to outline the stain. Then gently scrub the area where the stain is. Be careful not to scrub too hard, as this could damage the sheepskin material. Combine 1⁄2  c (120 mL) of warm water and 1⁄2  c (120 mL) of distilled white vinegar in a small bowl. Take a washrag and dip it in the mixture. You want the washrag to be damp, not soaking wet. Dab at the stain with the washrag and gently rub the stain out. Remember that too much water can damage the sheepskin, so don't saturate the washrag. If you get an oil or grease stain on your Ugg slippers, try using a bit of chalk to get it out. Just sprinkle some of the chalk onto the stain and let it sit overnight. The grease will absorb into the chalk and leave your Ugg slippers looking brand new.  In the morning, brush away the chalk and the stain will wipe away with it. You can also use cornstarch and talcum powder instead of chalk. Clean out any hair or debris that has accumulated in the bottom of your Ugg slippers. Then pour a few drops of mild dishwashing liquid on a damp washrag and scrub the insides of your slippers.  Don't use too much dishwashing liquid or the insides will get too soapy and it will be hard to clean out. And make sure your washrag is just damp – not dripping wet. You don't want too much water inside the slippers.

Summary:
Use a pencil eraser. Clean with vinegar. Use chalk to remove oil or grease. Scrub the dirty fleece lining.