I use a battery operated dremal tool found at WAL/$20. with the sandpapper round. It has a slow setting that works good for spurs or toenails, even beaks. That is what some Vet offices use....Other times I will despur them. If you have some blood clotting powder than you can squeeze in the middle of the spur with wide pliers and it will pop right off, it will bleed ,so use the powder. What is left is a soft quick, that can be filed down after a few days, little at a time.
The best, and longest lasting method for dealing with spurs is to cut them. You can see detailed information on how to do this on my site HERE . Good luck!
If you simply want to remove the tips of the spurs (don't have 3" `sabres' that parry, clicking, as the guy trots along), heavy grit emery boards will round away the fearsome business ends pretty quickly (will be able to whack away at your mudboots but won't puncture them). If more is required then the above posts cover those situations. Doesn't hurt `em.
Thanks to all. It looks like his spurs are about two inches long. I have one of those tools but was unsure of how far to cut down. thanks for the website link CUDA that really helped. Chris