Define safe. Do you want something to use while you have plants or caterpillars in there? Typically a bleach solution is going to be one of the few things that will work and is inexpensive enough. Obviously you can't use that while you have caterpillars or plants in there. If you remove both and use the bleach solution (let it stand for ten minute) then rinse well it should be fine. Bleach also loses its potency over time in sunlight.

Just as a note, wood is not the best material to use for cages for this very reason. It is very difficult to clean when concerned with disease.

-Elisabeth

Safe as in safe to use on plants and caterpillars, the same as they sell on Live Monarch.

In any event, I removed the enclosure from the garden, moved the cats to a large container temporarily while I scrubbed the frame with a bleach/water solution, rinsed it down and let it dry in the sun. I have also lined the bottom with sand and then newspaper so that I can change this daily.

Thanks for the suggestion.