drugstore.com has a 4-pack of Mr. Clean Original Magic Eraser Disposable Household Cleaning Pads for $3.34 - 15% off with this link
with free shipping on any order with ShopRunner or on orders of $25 or more. Otherwise, shipping is $6. Or you can buy two packs for $4.18
when you click "Online Coupon: Click & save an extra $0.50 on Mr. Clean" under Special Offers on the product page. Has a legendary reputation for cleaning gadgets when used with a small amount of water.