I found this article and will past part of it, it is from cakeplay: It answers some of the questions you asked.
9. Will my melted isomalt have a cloudy appearance?
Answer: CakePlays isomalt sticks are very clear. However, the substrate or mold used to cast the isomalt can give it a cloudy appearance, depending on the molds surface and/or density. Typically, a mold with a tighter structure will give better results. One technique to try for improved clarity is to rub a little vegetable oil onto the mold, then wipe it off before pouring the melted isomalt in. You can also use a crème brulee torch to restore surface clarity.
10. When do I put finished pieces on a cake?
Answer: CakePlay recommends placing finished isomalt pieces into an air-tight container until just before displaying your cake. If you live in a high-humidity environment, you may want to add a desiccant to the container with your finished piece. CakePlay has desiccant packets available in our online store. Do not refrigerate finished pieces.
11. Will CakePlays isomalt sticks work in a high-humidity environment?
Answer: Isomalt works much better than sugar in areas of high humidity, but will still absorb moisture, although more slowly, and will not crystallize. However, cake artists and pastry decorators will want to take some precautions when working with our product: (A) Immediately after finishing a sugar showpiece, store it in an airtight container with a desiccant such as silica gel. Do not remove the piece from the container until just before displaying. (B) Unused isomalt sticks can be stored in an airtight container away from light and heat for up to 2 years. (C) Leftover melted isomalt can be poured onto a Silpat mat, cooled and stored. Those in high-humidity environments can also protect their finished creations with an edible lacquer spray or confectionery glaze. Visit www.cakeplay.com
for more ideas and suggestions.
12. Can I burn isomalt?
Yes, but only with significant overheating. This is why we recommend adding time to the microwave in small increments. When melted properly, isomalt can be heated multiple times. Typically, the color breaks down long before the isomalt, and you should be able to heat the product a few times without detrimental effects.
13. My molded piece looks cloudy. What should I do?
There are a number of factors which may be causing the cloudiness in your finished piece: (A) If youre using a silicone mold (or some silicone mats), the silicone may not have been cured properly during manufacture. Only use top-quality molds. (B) Excess humidity in your area and/or preparation location can cause cloudiness. Use desiccant packets when you store your finished pieces to alleviate this issue. (C) Lightly run the flame from a crème brulee torch carefully over the molds surface to remove cloudiness. (D) Lightly rub oil onto the molds surface, then remove the excess with a clean cloth or paper towel. (E) Do not refrigerate molded pieces. Store in an air-tight container until just before display.
14. My melted isomalt has bubbles. How can I eliminate this problem?
If bubbles occur along the surface of the isomalt next to the mold and are quite small, the mold is the problem. The type of mold and quality of mold can affect the end results. Silicone molds give the best detail, but depending on the material and cure rate, can cause small bubbles on the surface. These can be removed with a minor loss of detail with the careful use of a crème brulee torch. Another approach some people find helpful is to run a small amount of oil into the mold before pouring in the isomalt, to create a barrier between the two materials.
Be sure to let melted isomalt stand for some time after microwaving for bubbles to dissipate. If the bubbles are truly in the center of the mold, this is the most likely culprit. Watch through the window in your microwave to avoid heating the product longer than necessary, thereby forming excess bubbles. This is especially true if you are microwaving a small amount of isomalt.
A good pouring spout helps to eliminate some bubbles as they stretch and break as the isomalt is poured into a mold. Also, after pouring, if there are small bubbles on the surface of the poured isomalt in the mold, and your mold is heat-proof, these bubbles can also be eliminated with use of a crème brulee torch while the isomalt is still liquid. Be careful not to heat the isomalt to the boiling point again with the torch a light touch is all that is needed.