My iPhone 4 won't turn on? - 4

I have a phone but not an iphone 4. BUT, me and my friends were walking and I found an phone in the grass and dirt. So I took it home and wiped it down (NOT with water) and cleaned it out. So I didn't put any water in it, so I put it in the charger and it began to work.

Although the person shut down the survise so I couldn't call or text, but I could do anything else cause it wasn't locked.

Well, then my family and I left out for dinner, when I came back I tried to turn it on. IT WON"T TURN ON. I don't know why, it was working perfectly. So I was messing with it trying to turn it on, and well I don't know anything about the iphone 4, but the top button on the side when I switch it over it vibrates.

Its making me very frustrated. Please help! And thanks!

Added (1). I just realized the first to sentences make no sense, ME AND MY FRIENDS FOUND AN IPHONE 4

Added (2). I just realized the first to sentences make no sense, ME AND MY FRIENDS FOUND AN IPHONE 4

Try to return it lol but try holding down the home button and the lock button at the same time

There are three possible things that could've gone wrong. 1. The owner of the phone had warranty on the phone and Apple deleted the number code on the iPhone's system so now its just an iPhone shell and there's now way it is possible to fix this legally. 2. Some dirt gone into the screen so now its not functional it can be easily fixed in any phone unlocking/fixing shop for £10-£20. 3. The Phone is in recovery state try connecting it to iTunes and reboot it through computer (iTunes is a program for apple devices its free). The button on the side is to mute/unmute device. If device vibrates when muted/unmuted then its good news for you and probably number 1 is not included.