Telling twins apart

Leidy
My twin identical girls will be home together today or tomorrow from the NICU. I've had one twin home for 2 days. So far it's been going well. She has figured out she's not at NICU and awakes every 2 to 3 hours instead of 3-4 hrs. At least we have practice with one twin. We went to see the other twin at the hospital and they make the exact same sounds. We just want to get ready. 
Twins mom out there I want to try using the nail polish method to tell them apart. I went to whole foods and bought mineral fusion nail polish. It's organiz and vegan. It seems it's a safe product to use. Has anyone used this product on their kids ? Does it seem safe to use on infants? I'll ask my pediatrician tomorrow. Thanks. 
Flawless Application: This long-lasting, chip-resistant nail polish applies flawlessly with our custom, extra-thick brush.;Formula Purity: 100% Vegan :: Toluene Free :: Camphor Free :: DBP Free :: Formaldehyde Free :: Cruelty Free;Free of formaldehyde, toluene, camphor and dibutyl phthelate;Custom, extra thick brush for flawless application;Berry Cream