Future Floor Finish, a clear acrylic, is another popular choice for sealing polymer clay.
Any acrylic floor polish can be substituted for Future. Like Varathane, Future is cheaper per ounce than glazes produced especially for polymer clay. Acrylic floor finishes have the added benefit that they are available in most stores that carry household cleansers.
Future can be applied to raw or cured clay with a paintbrush, a cosmetics sponge, a paper towel, a soft rag-- even with your hands. It is also possible to dip items into Future, but dipping does leave drips that must be wiped away. For the shiniest result, sand and buff before applying multiple coats of Future, letting the piece dry completely between coats. Two coats are enough for many applications, but some people are happier with more. Putting coated pieces back into the oven for a few minutes helps set the finish.
It is possible to remove Future from polymer clay, if you change your mind about it. You can try rubbing off the finish after soaking the piece in water. If that doesn't work, diluted ammonia or products containing ammonia (like non-streaking window cleaners) are the next option. If all else fails, you can resort to a heavy-duty floor cleaner.
Some people caution that Future may yellow with time. Also, prolonged contact with water or high humidity may cause the Future to cloud or turn sticky. Future isn't quite as permanent as some other finishes, but many people are thoroughly satisfied with the results it gives.
Like Varathane, Future can be mixed with acylic paint, inks, mica powders and other materials to produce colored glazes. Mica powders mixed into Future make paint that works well for crackling techniques.