Just saw this on YouTube on how to refresh your old strings to sound new without taken them off your bass.
http://m.youtube.com/watch?v=s8OYeN9mAL4&desktop_uri=/watch?v=s8OYeN9mAL4
http://m.youtube.com/watch?v=s8OYeN9mAL4&desktop_uri=/watch?v=s8OYeN9mAL4