Excellent news! I would lightly treat their substrate, and around the lip of the cage just to stop any wandering mites from getting anywhere. (I'm paranoid about that sort of thing)

Rats are highly motivated by treats. Yogurt drops, yogurt covered raisins, anything they really love. When you go to say hello and play with them, make them come for a treat. They will start to learn you give them goodies when they come to say hi.

I find another great motivator for getting shy babies to trust you is to play with them for as long as they have the energy. I take away any hides and tickle and chase them with my hand. If you play with their siblings, they will want to join in the fun.

Even if they dont want you to touch them, they will start getting so curious about all the ruckus. This has worked many times for me to get those shy rats to trust me. We do it every night for a few weeks, and before you know it they will be begging to come out and play.

Once they have control of themselves better, I start to carry them around in my hoodie pockets and walking around the house with them, just to get them used to us.