Alcohol is your friend!
I passed this tip on to another blogger recently and figured that it was worth posting here. I learned this from an antique dealer back in the early 1990s. He was putting some furniture up for auction that had some dings in the wood that he wanted to obscure. He pulled out a permanent black ink felt tip marker (alcohol based) and dabbed it on the ding. Then he rubbed it with his finger and "voila!" The light colored ding was gone. Having recently done some floor finishing with aniline tinted shellac I got to play with the alcohol/dye solution a bit and discovered that aniline dye is used to color ink AND wood stain. So, if you have a ding in your original woodwork and are tired of it being noticeable, try this out. Of course you could always use a brown marker pen if you think black is too harsh.
Something called Lac paint was common at the turn of the century. This was an alcohol based colored shellac. I recently acquired a free lockset with red colored porcelain door knobs that appeared to be chipped. I wiped them with denatured alcohol and the red color came off leaving perfect white porcelain which is what I wanted anyway. So, alcohol IS your friend!