How can i clip my coackatiels nails?

I have a male coackatiel who's about 8 years old. I don't think we've ever clipped his nails and I'm a bit worried. They're starting to get snagged on things. Are you supposed to keep the nails/claws/talons clipped or do you just let them grow? If you are supposed to clip them, what can i clip them with? Do i have to buy something special?