Rusty

I pulled out my jack the other day just because I'd never bothered to look at it before. It was rusted on one end. I reached down into the cavity and there was 3 inches of water in there. It was slippery and stinky too, I 'bout barfed, grossed out. I can't tell where it came from, it's all sealed where I can see.
I sometimes use a touchless Laserwash, and when you slowly enter, it hits the underbody and wheels with high power spray. That's all I can figure. There may be a plastic plug to drain it. If it happens again, I'll either pry it out or punch a hole in the lowest part. Y'all may want to check your P5s. I don't know about sedans.

alex_aha

i think this has been discussed before, basically its your taillights housing that is leaking.... but if you have a nice subwoofer in your car you may have unintentionally loosened some seals in your trunk...

Omron

That stuff is normal and my guess is that its possible it could be factory, i noticed it one time after i was cleaning my car and had a undercoat put on, for me it was a purple pink color, sticky, about an inch but not touching the jack, but ya i am sure if you pull up your carpet in your trunk you might notice it on the other side or in any other cranny, i am betting its just to prevent rusting.

Dragonbreath

Switch from boxers to briefs - it helped me!

Rusty

Naw, briefs are too constricting. They make my ******* sweat, and then I have to sneak the old pocket peel
Besides, I cleaned the rust with WD40 and coated it with 20 weight, and bailed out the scum. No mo problemo.