I welcome all suggestions.
Well if there is not already crud down in the air gap between the magnet and the voice coil there is one thing you could try. It kind of looks like the cone is warped so this might work.
First you need something to use as temporary shims between the voice coil and the magnet. You might have to experiment a little, but something like 1/4" strips cut from a business card might work. If that is too tight you might have to resort to something thinner.
What you want to do is shim all around between the magnet and the voice coil to make sure there is guaranteed clearance between them. Once you have this in place then mist the cone with water from a spray bottle. Make sure it is all damp. Then let it dry. With a little luck you might be able to un-warp the cone enough to stop the voice coil from rubbing on the magnet.
If that is accomplished then glue a little circular piece of felt over the center to protect the gap. A little white glue works fine for this. Don't get anything in the gap. You are just trying to cover the opening so stuff doesn't get in there.
If this doesn't work you are probably looking for someone to re-cone it or looking for a replacement speaker.