Question
I have what I believe to be a wandering jew or creeping charlie.  It is over 20 years old and until a month ago, very healthy.  It faces out a north window and receives basically indirect sunlight and water weekly.  This has kept the plant thriving and trailing over the staircase nearly to the floor.  Our cat has recently taken to using the plant as a litter box and subsequently, the leaves are dying and the vine withering.  I have transplanted the plant in new soil and covered the opening so the cat cannot get into it but the plant continues a downhill slide.  I love this plant, any advice?

Answer
Oh, boy.

First: Take some cuttings.  If you face the Worst Case Scenario, at least there will be Plan B sprouting roots in the window.  Use a razor blade and make sure the rooting medium is kept moist and not cold.

Pet urine won't merely contaminate the soil; it will burn the roots of anything growing there.  Too much Nitrogen in one place, at one time, is poisonous.  Nitrogen is a waste product in mammals.  It's what you have left over when your body uses protein.  Cats have even more protein in their diet than dogs and people.  That's just more bad news for your Wandering Jew.  It's sort of like someone with Rabies; once symptoms appear, it's too late.

Transplanting was a good step.  It just was not enough.  Treat your plant as though most of the roots had been removed.  Gentle bottom warmth will encourage growth if there's any life left there.  And if there are any roots left, your plant will need extra Phosphorous (the "P" in N-P-K) to grow a new root system.  You'll get a slow, steady dose with Bone Meal added to the soil mixture.  Do not -- I repeat, Do not! -- give this plant Nitrogen.  It would be like giving heroin to an O.D. patient.  Whiskey to a cirrhosis of the liver victim.  A rap on the head to someone with a big concussion.  Is that clear?  No Nitrogen!

Reason being, the plant will decide to grow leaves, and it's got enough trouble sustaining the ones it has.

The enormous amount of topgrowth on this plant of 20 years will only be a strain to the rest of the plant.  So a severe pruning of all limp leaves will be good for it.  Just gives you more cuttings to root.  They should be around 3 inches long and you should save them all.  Just in case.

Someday, maybe in our lifetime, there will be a more reliable way to save plants whose roots sytems were burned by Nitrogen.  Maybe we'll just get better at treating it.  If there is hope for your plant, this is the way to do it, the best way I know.  Please keep me posted.