I think that part of the problem might be the small number of people that attend your sales.
If 50 or 100 people pass through your yard sale it is quite possible that none of them will find anything that they are interested in and those that do may still have an issue with size, color, price, condition, etc...
I would try the yard sale and then take the leftovers and box them up for a trip to a charity shop or the curb.
Trying over and over again to sell the same things reminds me of this old quote attributed to Albert Einstein “The definition of insanity is doing the same thing over and over again, but expecting different results”.
Life is too short, just let the stuff go and move on.
Good luck!