I was in a pawn shop yesterday looking through a cabinet of old dusty lenses when I commented to the owner that they were all very dirty. I had a Bushnell 135mm f2.8 in my hand @ the time & he said let's see. I handed the lens to him & he wiped a thick layer of dust off the rear element with his finger & said "ya they have been in there a long time". I had no intention of buying but out of curiosity asked him what he would sell it for & he said $10. I thought why not & bought it, even though I had a Sears 135 already. It actually cleaned up pretty good.
This morning I set up a tripod on the balcony & shot two frames with each lens; one wide open @ f2.8 & the second @ f8. The Sears seems to have a slightly wider field of view & is a tad sharper in my opinion.
Assembling the pics together knocked the quality of the images waaay down.