Most of the antiquing that is done on carvings is done by painting the surface first with whatever colors you want, and then when dry, applying an antiquing color, usually burnt umber, thinned with boiled linseed oil, and wiping it off. You can't get all of the antiquing color out of the carving recesses, so it darkens these and makes it look old. Caution note: if you use boiled linseed oil, any rags/paper towels you wipe must be disposed of carefully, as they can spontaneously burst into flame. One method of disposal I've read is to put them into a bucket and then fill the bucket with water. Just make sure you don't leave them inside the house or garage.