Last night I went to a friends house to comfort her after one of her pets passed (a turtle) and I’m helping her get rid of the old tank when I see another tank in the room. I ask about it and learn she has a gecko…   
I left with that gecko and we are no longer friends (we had an unrelated fight).  
His tank was absolutely horrific and covered in a mountain of feces and dust. Smelled horrible. He had no water, and she told me she doesn’t even remember the last time she fed him. Somehow he doesn’t look too bad? Maybe slightly underweight but I’m not sure.. I’m not very familiar with leopard geckos.  
I spent all morning cleaning his stuff and setting up a very rushed last minute tank. He has fresh water and a heating pad now, and I need to stop by the pet store to get food today. (What’s the best thing to feed them? I’ve only had bearded dragons b4)  
The most concerning thing is that he wouldn’t open his eyes. I soaked him and tried to wash his eyes out, and when they got open they seemed to be covered in a layer of mucus or something? Maybe from lack of use or something? He’s just kinda been laying still since I got him (although now he’s exploring his freshly cleaned tank)   
I’ll include pictures but they aren’t the best bc he was already stressed and I didn’t want to over handle him.  
His underside looks perfect and his skin looks ok to me, he is missing a few front toes- which I’m guessing are from shedding problems and neglect.  
Anyway I’m just looking for some guidance and advice when it comes to the tank and cleaning and feeding.  
I want to give this cutie a better life :,)

Help with rescued gecko