They can be taken out, but it can be a pain and sometimes it is inevitable that you may damage the shaft beyond repair. If a shop did this, I would take it back to them before you run the risk of damaging a $10 arrow.
However, here are things that I know you can try, listed in order of not damaging the shaft.
1. Take nock out and put a drill bit in the shaft and "swing" the shaft letting the drill bit punch the insert out. Be careful though because sometimes when the insert comes out, the drill bit will be flying out with it.
2. Heat a pot of water to just about boiling and place the point end of shaft, with field point screwed in, in the water for about 10-15 minutes. Take shaft out and with a pair of pliers start working the point/insert out�it may take several times.
These next ones are a complete gamble and run a very high risk of damaging the shaft.
3. Take a drill bit and drill out the insert inside the shaft�be very careful not to contact the shaft.
4. This will almost always get the insert out, but at least 50% of the time will damage the shaft! Screw field point into the insert and with a propane torch heat the end of the point slowly for 10-15 seconds, the heat will transfer down to the aluminum insert and will heat/loosen the epoxy. After 10-15 seconds, take pliers to the point and try to work insert out�repeat process until the insert breaks free. **Caution** Carbon does not like a lot of heat, really doesn't like any, so even if you get the insert out carefully inspect the end of the shaft for small hairline cracks.
There maybe other ideas out there, but these have worked for me over the years.
