You’re right that there should definitely be some kind of ventilation in a bathroom to prevent moisture build-up. My husband and I are remodeling our bathroom and removing the window that is attached to one wall (it’s just so awkward having one there) and installing a vent to replace it is definitely something we’ll want to look into. I’m not sure if we already have an inlet valve, but our toilet can be rather noisy, so we’ll have to talk to the contractor about that, as well.
For larger nail holes, you can use a similar method as above, but the crayon will stick in the hole better if it’s just a little bit more soft and malleable.  So take a lighter and warm the crayon, just a little bit.  Be careful here.  You want it just a little softer, but not dripping all over the place.  You certainly don’t want hot wax dripping all over your hand. Then rub the soft crayon over the hole.  Wait until the crayon in the hole sets. Then you can rub off any excess with a dry rag.
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