We used to use Sculpey Gloss glaze, but it seemed that every time we used it it would harden around the top of the container, and it began to turn cloudy after not to long of purchase. So we decided to try "Triple Thick" Brilliant Brush on Gloss Glaze. It is super durable and super shiny, the sculpey glaze costs about 3-4 dollars, and the Triple Thick costs i think 6 bucks and you get WAY MORE than you do with Sculpey.
We bought Triple Thick at Michael's and we live in Eastern NC, Triple Thick is made by DecoArt and I would high recommend it.
The following is a link to the website for DecoArt but then you will at least know what it looks like. At Michael's here in NC I believe it was located with the "Modge Podge" and other things of that nature, where as the sculpey glaze it usually with the sculpey clay.
http://www.decoart.com/cgi-bin/Products.cgi?Triple_Thick_Gloss_Glaze