Note: It may be difficult to hear the differences on small, inexpensive speakers.

Noise Reduction Examples
1. 78 RPM - Clicks, Pops and Hiss BEFORE and AFTER
2. Reel to Reel - Hiss BEFORE and AFTER
3. LP - Clicks and Pops BEFORE and AFTER
4. *Cassette Tape - Extreme Hiss and Low Volume  BEFORE and AFTER

* Before applying any filters, I increased the volume of the tape in the "Before" example so it could be heard. Unfortunately, this brings up the noise level as well.  Also, the tape only contained audio on the right channel. I increased the volume level, converted it to mono so the audio would be centered and reduced the noise level as much as possible without effecting the voice.

Physical Cleaning Sound Examples  

Before and After cleaning

Cleaning Example
Clicks and Pops BEFORE and AFTER physical cleaning.

Here's what the Before and After wave forms look like.