SMS88 said:
Before selling the whole lot for much less than the breakup price it is worth checking that there are no single cars in the $100- $1000 price range. A lot of HW will only be $1 cars but there are some very expensive cars in the numbered range, and selling them in a lot for a buck a car or less would be selling yourself short.
I paraphrased the above.

Definitely check a price guide to see if you have any diamonds in the rough. Numbers to look for would be #1, #7, #10-#19, #21, #27, #30, #50, #51, #83, #271. I'm sure I'm missing some but it's been a while since I was up on these. Also there are extremely rare variations of some of the lower numbers with gold ultra hot wheels. Some are common with these wheels, but some are not.
Shipping can be prohibitive too on large lots. You may have to send several small boxes rather than a few larger ones.
Good luck with it!