The opposite of "be-griming," which means to cover or smear with dirt, grime or soot, could be "cleansing" or "scrubbing." These two words denote the act of removing dirt and impurities from a surface, whether it be a person's skin or a household fixture. Another antonym could be "purifying," which emphasizes the removal of any harmful or undesirable substances. Additionally, the word "polishing" can be used as an antonym as it implies the action of making something shiny or smooth by removing any unwanted marks or dirt. These words all imply cleaning and purifying, the opposite of be-griming an object.