There is no harm in contacting them...try to do so from a blocked number, lest you get a spike in calls from them. Don't give them any personal information other than your name at first.
What you want to do as ask them for a "pay for delete," which is when they remove the collection from your account completely in exchange for payment in full. Don't be surprised if they refuse--most collection agencies I have dealt with are far more interested in ensuring your nose is rubbed in your financial mistakes for the next decade than they are in actually making money and letting you move on. Sad, but true. If they do commit to a pay for delete, BE SURE YOU GET A WRITTEN AGREEMENT. Verbal agreements and understandings carry no weight.
If they do not agree to delete the reference, don't bother. FICO DOESN'T GIVE A RAT'S HIND END WHETHER AN ACCOUNT IS PAID OR NOT. Amazing, but true. Always bear in mind the credit system is much, MUCH more interested in punishing you and rubbing your nose in the problem for as many years as possible than it is in helping you reach a mutually beneficial agreement with your creditors.
If you cannot get the charge-offs or collections removed from your account, forget about trying to improve your credit if your score is below 600; you're spitting into the wind. For almost a year now I've done everything possible to "rebuild" my credit and I'm actually DOWN about 12 points from where I was last year at this time. Check back again in 2015 or so and see if the collections have dropped off your account.
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in a credit-scoring postnuclear Stone Age...