Vaseline is a tough stain to battle because of the grease in its composition. Even after regular washing, you may wind up with an oily stain that even time and several washings won't fade away. You can use a number of different techniques that require little more than basic household cleaning agents to remove Vaseline from your sheets.
Blot up as much of the Vaseline as you can with a dry paper towel. The more you can get rid of by hand before you start scrubbing the stain, the better.
Mix 1/3 cup of lemon juice, 1/3 cup of white vinegar and 1/2 cup of hot water. Stir thoroughly before applying. Pour the mixture directly onto the stain.
Scrub at the lemon juice, vingar and water mixture with a scrub brush. The acidity of the vinegar and lemon juice will help break down the petroleum in the Vaseline.
Rinse the stained area of the sheets with hot water. Rinse your scrub brush as well.
Pour a tbsp. of liquid dishwashing soap onto the stain. Scrub the dishwashing soap into the stain with your scrub brush until the fabric is white with soapy foam.
Rinse the dish washing soap from the stained area of the sheets with hot water until all of the suds are washed away. Wring the sheets of excess water.
Spritz the stain with liquid stain remover, and allow it to settle in for at least 20 minutes. Wash the sheets in hot water with your regular laundry detergent.
Inspect the stain after removing the sheets from the wash. Do not load the sheets into the dryer as the heated air will bake in any remaining stain, making it impossible to remove. If you can still see the stain, repeat the above process.