The ONLY last thing I would add.
I'm sure you will notice a lot of eCommerce websites will keep products that they don't sell anymore, and just keep them as "sold out". People still hit those products and land on those pages.
Check and see how often people are hitting these products. If some of these pages have some juice left, it might be worth recreating a page in its place for a product that isn't being sold anymore and up sell for something you are selling. Or as Ricky said above me, 301 them.
Don't just prune everything at once. Slow and steady wins the race. Make sure you know what you are cutting before you cut it.