How about trying a fogger??
at least that is what we call them over here.
You can normaly find them at "nurseries" or where ever you get your plants from. Some pet stores also sell them but they double the price because there is a pic of an iggi on it.

I also actually have a question on humidity.
What would happen if it is not kept to required levels.
The reason I ask is spike lives in an enormous cage so to keep levels so high is almost not practically possible but I have gotten Spike to Lay in her water bath its an oversize cat litter box filled with water.

If the air they are breathing is too dry it dessicates the tissue of their lungs. It can also cause shedding problems.

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Merlin,
What's Life Without A Little Magic!