Here are two videos from the guys at iZotope that show how to resolve some audio problems. The first one can be a common problem in both vocal and voice over sessions and we have toched on this is one of our podcasts.

See how to use RX 2 for removing and reducing unwanted mouth noises, plosives and other artifacts common in dialog recording. In this example, we reduce the sound of some wet clicking and several plosives.

In the second video you can see how to use RX 2 to restore recordings transferred from old records by reducing clicking, crackling and noise. In this example, we reduce the clicks, pops, time-variable wear variations and general noise without harming the character of the music, which was originally from a 78rpm shellac record but the problems are sme for Lps at 33rpm or singles at 45rpm