A coffee percolator can be cleaned without soap using various household items, such as white vinegar, baking soda or cream of tartar. Lemon juice is also an option for those who do not like the smell of vinegar.
To clean with baking soda or cream of tartar, add 2 to 3 tablespoons of either substance to a full pot of water, around 8 to 12 cups, and run the percolator as normal. Scrub the remaining residue away with a nonabrasive brush after the water cools. For those with hard water, a second cleaning with vinegar or lemon juice is suggested. Use a mixture of one part water and one part vinegar and run the percolator as normal. Rinse the percolator after cleaning.