I tried a beer, milk, and moss recipe but got no results. The directions at that link did mention to let the gathered moss dry before applying with the mixture. I didn't do that so maybe that was one cause of failure. Really like the appearance of mossy or aged pots.

I would wait for spring since it is usually best to bring clay pots into a garage or shed before the freezing temps hit-unless you aren't planning to plant in them. If they are purely decorative and you aren't worried about cracks, then it probably doesn't matter.

they do need to be set in dappled sunlight and in moist condition to be effective.

thanks everyone