My sister dropped her iPhone 4 in the water, I tried fixing it and failed. Several months later I decided to attempt fixing it again, I finally got it to work. It has been working flawlessly for awhile now and I've decided I wanted to sell it. She has a new phone, she has even switched to ATT from Verizon. My question is, is the ESN clean on my sisters old iPhone that I fixed and now want to sell? And if it's not, would it still be safe to sell online?