[Atomic-S (OP)]

Can damp calcium chloride be restored to the dehydrated state by heating without it undergoing decomposition, and if so, what is the recommended temperature?

[chiralSPO]

I think it is possible, but not worth the effort. Anhydrous calcium chloride is pretty cheap, and if you're storing it in a way that it's getting wet, the problem will only continue (and it's gonna get really wet).

[chiralSPO]

a quick google search recommends 200 °C overnight, but may take longer depending on degree of hydration. You might have to stir it a few times (but be careful because it's likely very hot and very sticky!)