Vaughn, the alcohol at that level will be rather mild in effect against the beasties IMHO. The UV will not have much effect due to the black blocking power of the carbon (imagewise) but it will also have some effect.

Thymol, Phenol and Kathon are better, but Kathon comes with some metal preservatives and you just about need EPA approval to use it. You can burn yourself with Phenol, and its sale is restricted in many states. That is why I use Thymol and why I am working to find another preservative.

These comments about preservative action of IPA and UV are just guesses based on some limited experience.