One Audiofile of my class (Three Healthy And Delicious Alternatives To Jam And Nutella) was especially terrible, so I cleaned it up according to the instructions in your class. Everything worked out fine, altough it was a little bit complicated as it combined the Audiotracks of two different cameras...
My version of Audacity seems different to yours. At least I had different parameters in the "Reduce Noise" Window.
Unfortunately I don't have time to edit the other tracks, but I hope they will accept it as it is.
Here is the link to my class: http://skl.sh/2duXphZ