The problem with space debris is that many of the pieces are in drastically different orbits - especially the debris from ASAT tests - and there's no easy way to deal with that.

It's quite expensive fuel-wise to get from one orbit to another - especially at the altitudes where debris is the biggest issue - and you will need to somehow capture debris that might be coming at your satellite at thousands of meters per second of velocity. You need to make sure it doesn't hit your satellite and create more debris.