Spring steel/couch springs - Worth more than regular steel?

You normally will have to ask your yard for their definition of categories. Many are similar but each allows different things to slide, especially when you are a higher volume and regular customer.

If they are big enough to qualify at your yard as heavy or better grade than shred, then by all means separate them as it is extra money in your pocket. The yard will have a final say though you can normally get away with tiny amounts of lighter stuff sprinkled in without being penalized. Just don't over do it and take advantage of them allowing you fluff. If you do they will pay less and get very picky checking your loads or down grade loads you bring in for the smallest amount that don't belong in the category you are trying to sell as.

If you have a large quantity of them just leave them separate and bring them in separated from the rest of the stuff and ask what they classify them as. At worst you may end up tossing them in with shred but then you know in future if its worth the time.