The larger Swarovski Rivoli crystals like the one used in this scarf charm below, don't come as "hot fix" so we have our own method of securely fitting them into our designs.
We always have a wide assortment of Swarovski crystals in assorted colors and sizes to work with and found the little pill containers work great for keeping them all sorted and organized.
Some of the clay techniques we do require sealing such as applying mica powders or inks. They will go through a process of two types of glazes, the first of which is a spray called Preserve Your Memories 11 (PYM11). When applying the spray onto pieces that have Swarovski crystals embedded can leave a film over them so they require cleaning. I have found that the Alcohol Blending Solution by Adirondack, works beautifully for this. I just add a bit of the solution to a q-tip and wipe the crystals until they come clean and their sparkle returns. I usually do this after applying the second type of glaze and before baking the pieces to harden the glaze.