One way to avoid boil over marks on your stove top is to use large enough pans when cooking. Sometimes it's unavoidable, and the boiling contents from your pan can spill over onto the stove top. When possible, immediately wipe up the mess. If you can't clean the boil over immediately, cover it with salt to make clean up easier. If you don't wipe up the mark immediately and you fail to douse it with salt, there are other tactics to employ to make cleanup easier.
Soak a dishrag in hot water and wring out the excess water.
Lay the rag on the boil over mark. This helps to loosen the mark. Let the rag set for about 10 minutes.
Add a little water to several tablespoons of baking soda. Use just enough water to make a paste the consistency of toothpaste.
Remove the towel and dab the baking soda paste on the mark. Let it set for about 10 minutes.
Scrub off the mark and baking soda paste, using a clean wet dishcloth.
Rinse the area using a dishcloth moistened in white distilled vinegar. Wipe down with a clean wet rag.