How do I safely remove old wiring?

I am renovating a garage and turning it into a 2 br apt. The space has some old wiring. I will be tearing out the sheetrock, exposing the wiring. What's the best way to get rid of the old wiring? From the panel? Cut it and throw it away? What? Yes, I'm a novice at this. I only know enough to cut the power to everything before I do this.