New Gerbils

First thing I need to mention is that blowing on gerbils is how researchers induce seizures in them in lab studies, so please don't do this, it's extremely dangerous. With the biting, if she's biting you when your hand is going into the enclosure, this will likely be because she's feeling scared and threatened, if you then punish her when she tries to defend herself (as she sees it) all this will be teaching her is that she's right to be afraid and attack, and will likely just get more and more forceful with her attacks. Your best bet is to stop putting your hand in the enclosure completely while she's awake. If you do see her up and about, try offering her treats (ones that she doesn't get any other time) at the door, keep your hand outside of the enclosure and let her come to you, this will help to teach her that (a) hands bring good things and (b) she has control over the situation as she can approach, or not, she has the choice to interact. This should help her to feel safer and more confident around your hands and should help to ease her fears. If you are still having issues with her biting when doing this, try wearing a biteproof glove and keep your hand very still, even if she bites you, just stay still, don't react and make sure you have some high value treats in your hand for her to take when she feels comfortable enough

It may help if you spend some time talking to them, to get them more used to your voice, even if they're in their burrows. How much time are you able to spend with them when they come out in the evenings?

When they are out in an evening the children will talk to them and offer them treats, through the bars initially and then if the gerbils are confident they'll open the door and offer treats on the hand. But it's such a slow.process and they often just run off and that will be that so it difficult to get anywhere with hand taming and I could really do with cleaning them out.

For cleaning them out, you can use a tunnel/tube of some kind and get them to crawl into it to remove them from the enclosure. It sounds like you are making progress, some gerbils do take a bit longer to tame than others. I also noticed you said you remove their millet sprays during the night, I would be more inclined to leave it in. If they're nervous coming out when people are around they're not going to see the sprays in the topper as much, the point is to give them positive reinforcement just for being out to start with, so by leaving it out during the night, they learn it's a good place to be and may come out more during the day. I also recommend talking to them during the day as much as possible so they can get used to the sound of your voice, see if those changes can help 🙂