Circus Train Cars - Collectable ?

I was recently given several boxes of unopend rolling stock, clost to 1000 boxes. Of those approximately 100 or so deal with circus. They are from several different manufactures, but a good many from Welthers. Most of these boxed pices are approximately 10 to 40 years old. Does anyone have an idea on the worth, or should I just try to sell them one by one at a yard sale. Any suggestions or comments are greatly appriciated.

I WOULD CALL “WELTHERS”,OR FINE A TRAIN STORES IN YOUR AREA>>>>>>>>NOT A HOBBY,BUT TRAIN STORE,SOMEONE SHOULD BE ABLE TO HELP OUT…GOOD LUCK

IT MUST, BE WALTHERS ,NOT WELTHERS & THEIR PHONE NUMBER IS 1-414-461-1050, OR 1-800-487-2467,THEY JUST PRINTED THEIR 5 EDITION BOOK OF BIG TRAINS,HAVE ONE IN HAND,YOU DIDNT SAY SCALE SIZE MUST BE HO.