Thanks welshblue, and everyone else too.
I tried adding the extreme edge fader (found it in the link you sent which is to a long list of plugins, but the direct link is here) and followed the video tutorial that was listed at the link as well. Couldn't get the plugin to even show up in paint.net 3.x, so I downloaded the 4.x alpha and it shows up there. Followed the video tutorial listed with the edge fader on a random image I had. Weirdly, it didn't do anything to my image no matter where I put the slider on the fader. I checked the tutorial again and the only thing I can see different on the tutorial image is that it has the checkerboard that would indicate transparency, and I know it worked in the tutorial. So, I am sure I am just doing something wrong, but can hopefully figure it out
Also, you said about soft eraser in 4.0. Is that another plugin? I tried looking through the different effects and did not see a soft eraser listed at all...
Thanks again!