Last time I was in Germany I witnessed some tusks been removed. The lower jaw was removed from the skull and boiled until the tusks could be worked out of the jaw. The upper jaw was cut off across the bridge of the nose further back than where the tusks are located using a simple wood saw. This is not as simple as it seems as I believe only 1/3rd of the tusk are visible so you need to make sure you don't cut through the tuck when cutting across the nose. You need to go quite far back, depending on likely size of the tusks Once the nose has been cut and removed then it is also boiler. I'm not sure if this is the standard method of removing the tusks but it worked fine.
Like boiling heads down, the smell can be pretty bad. The chap dealing with the tusks threw some packets of soup in with the jaws which lessens the smell which I thought was a good idea.
Once the tusks had been removed from the jaws they suggested that some clear wood filler is used to fill the inside of the tucks. This apparently helps protect them but again I'n not sure if this is usual.