How to reset a used iphone 4?

I got a used iphone 4 a few days ago and i have no idea what the reset code thingy is. How can i reset it and delete everything off of it?

Tips for drawing on iphone apps?

So i installed an app to draw some stuff and i well honestly suck at drawing on anything except paper and pencil. I'm wondering if anyone has tips on how i would use my app. I can't erase my base correctly without effing the whole thing up. I'm drawing an anime style head portrait

I changed my apple ID but the app store still uses my daughter s old deactivated ID?

So IIm using my daughter s former iPhone 4 but she kept her account on there so I changed it and made a new apple ID for myself.
However, when I use the app store to update my apps I ll need to use her account. I entered her password but it simply says to retry but then it leads to this website where it says my daughter s ID has been deactivated. The thing is, I entered my apple ID on the phone (in settings-> itunes & app store) and my apple ID shows up on there. So I don't see why my daughter s deactivated account appears when I want to update. My daughter modified the settings so I would be able to have my app updated automatically without signing in.

Any help?

IPhone 6 charger got wet? SOS?

So a watter bottle got spilled inside my bag and my charger, headphones and USB flash drive were in it. I took them all out as soon as possible, dried them with some clothing and put them on a dry spot for about 2hrs (I was in the library). I got home and plugged the charger in and it appears to be working just fine. The part that goes into my phone was slightly warm but I gather it is normal? Is it dangerous to keep charging my phone with it if it appears to be working fine? It did slightly hesitate to begin charging at first but once it started it didn't stop.
As for my headphones, I tried them out immediately and they seemed to be working too. The flash drive still seems moist so I've put it aside for a little while.
IIm scared, will the charger damage my phone and will the flash drive damage my laptop?