Is there a "bssstt" noise in the recording also?
I have a tutorial on how to remove it with the program Audacity
1. Import your sound file.
2. Click on a small sample of the fuzz/crackling
3. Go to "effects" and go to "Noise Removal"
4. Click "Get Noise Profile" and press Ctrl + A, or Select your entire sound file.
5. Go back to "Noise Removal" and adjust the settings to your liking, you can use the preview,
6. When finished, hit "Okay" or whatever it says.