I don't know who invented plastic key bushings, but they should be
illegal.  Replacing key bushings is not a difficult task, nor that
expensive.  Don't waste your time doing something temporary, just to
undo it all again later to do it right.  Furthermore if you damage the
wood with the plastic ones, you will open a whole new can of worms.

I just rebushed a complete set last week, but I have to admit I don't
particularly enjoy doing it.  In this case I did it myself because of
particular circumstances regarding the piano's owner.  But normally I
send them out because it is so ridiculously cheap.  There are numerous
guys out there who specialize in key work.  You wrap them up, send them
off, and in a week they return with new bushings, ready to put back in
the piano, typically only costing around $150-$175.  I will send you a
few names and numbers.  Don't waste your time with mickey mouse plastic
things that never work.

Rob Goodale
Las Vegas, NV