[Bob Carriere]

Hi Terry

There may be a reason for having the original boxes waxed similar to the then available "butter boxes" now expensive collectable items.

In the case of the butter boxes they were waxed to protect the taste of the fresh butter and keep the butter from saturating the wood.

In the case of the battery boxes a deep imbedded wax would have protected the wood from accidental acid spills or splashes.
Once waxed no paint would be required or stick to the wood.

Bob C