You should still be able to use them. From my experience, I think what you'll find is that they have plenty of flavor, but might be lacking in sweetness. So, you can easily compensate for that.

Might not be good for plain old canned pears, but should be fine to make into a preserve or something, especially if it's a recipe that has other ingredients in it, to compensate for any shortcomings the pears might have.

Also, before you give up on them, try ripening a few in a bag with some other ripe fruit, and see what happens. They might surprise you.

grind 'em up and make pear relish

kay

Or pear mincemeat, I posted a recipe on the "I'm lucky" pear thread. Lots of other flavors going on there, so if the pears aren't quite as sweet, it's still probably OK.

Annie