Cottage Paint Furniture Clean and Prep is by far the BEST product for cleaning furniture (& a surprising number of other things) prior to painting. Just spray on, let sit for 20 minutes then wipe with a clean, damp rag. Repeat for very old, dingy pieces. You will watch in amazement as the years of polish, oils and dirt wipe away.
One particular surprising way to use Furniture Clean and Prep is with a magic eraser to remove liquid chalk products from chalk boards. All you do is spray on, let sit then wash away with the eraser! You will be amazed how much easier it is and how little ghosting remains.