Water damage caused the screen to go black, but still touch responsive
(Firstly I should say that it was on and charged) I accidentally left my iPod in my trouser pocket and it went through the washing machine (I found it just after the washer had finished) and instantly put it in the boiler room where the towels go to dry it out. After it was in there for the afternoon I tried to turn the screen on but to no avail. So I plugged it into my speaker set (Which also charges the iPod) and saw the screen flicker on and back off a second later so I touched the screen and the same thing happened. The iPod no longer flickers when touched however the blank screen responds to touch as if it were working fine (pauses the song when touching the middle, next/previous song when touch right/left) So I'm wondering if I only need to replace the screen? The computer recognises it as the iPod and the power and volume buttons all work.
You seem lucky enough to have your iPod still powering on and working despite what it went through. It seems no major component on the board was damaged.
I would suggest opening your iPod, cleaning it from the inside (the logic-board) with "contact spray" or isopropyl alcohol (at least 85%), slightly and LIGHTLY brushing it with a very soft/used toothbrush, drying with a hair-dryer, then replacing the screen with a new one.
This would help remove corrosion and soap residue, to avoid any further damage to any components on the board; because I'm assuming that the water and detergent that got into your iPod may have caused the board components to start corroding, and damage would potentially appear in a while.