There is no secret to cleaning them up with out paying. Even after you pay ,it can take months for it to be removed.
Depending on what state you are in , they are supposed to drop off after 5-7 years ,but this does not always happen. If you have something that is over 5 years it should not be affecting your ability to get credit , unless it is a car or home loan. The car people are less forgiving and go pretty far back. If trying to get a home loan , if you have a really good reason and correspondence , you can usually explain it away.
There is one secret , that if you contact the company directly , and set up payment terms , in most cases you can get them to reverse the account to "closed" with a balance. THis will look like you are in good standing and willl not adversely affect your credit rating.