Many Cymbal companies such as Zildjian, Sabian and Paiste make and sell their own brand of cymbal polish. Although they recommend that you use this polish on their cymbals, you can use just about any kind of brass polish on your cymbals. There are some important things to consider here:
-- Depending on the specific ratio of metals that were used to create your cymbal (which is hard info to get your hands on), various brash polishes can have an abrasive reaction with your cymbal. If you're not careful it is possible to remove the black brand labels from your cymbal with just about any polish. However, choosing the wrong polish for your specific cymbal could injure the actual face of the cymbal and damage the tonal grooves (the little ridges of a lathed cymbal) which would disrupt their intended acoustic properties. Most likely, you will be fine when using brash polishes, but keep this in mind.
-- If you just google "cymbal polish" you can find that just about everyone has their own magic polish. Some people swear by Ziff's cymbal cleaner, or Brasso, or Wenol, but the basic problem is the same: you spend forever trying to buff out the polish. Just about every time I have used standard brass polish or products like the ones above I end up getting really streaky looking cymbals, like the one below. I have also heard of people using household cleaners like Windex or dishwashing detergent and water. I haven't ever tried this but I wouldn't recommending experimenting on a $200+ cymbal.
My main problem with most brass and cymbal polishes is that they only account for the brass component of the cymbal. While this is the main metal used to make cymbals, many cymbals (especially the nicer ones) have at least 15% tin and/or bronze, and in some cases it can be higher. In addition the buffing process is no joke, and if you really want your cymbals to shine, you have no choice but to wear your arm off trying to get results. In the end, it usually ends up looking like the cymbal here, which leaves much to be desired. Don't fret though, keep reading.