Replied by Ted (Bangkok, Thailand)
Using iodine solution or colorless iodine (sodium iodide and potassium iodide) would be a much safer choice. Yogurt and cottage cheese wouldn't work, and garlic might be toxic to cats. Apple cider vinegar or vinegar sometimes work, but if it is not ringworm, it might cause inflammation since vinegar is acid and can get into the cat's eyes. I prefer a much milder solution of 1% H2O2 in borax applied topically. That's because once they evaporated, the only remains is a small borax powder. Iodine might cause some irritation, although not much and can be rinsed if it did get into the cat's eyes.
