How to prune hygienically your lavender plants

I prune lavenders in early spring and after flowering. So now it is time to prune. The more plants you have, the more important it becomes to prune hygienically. But how to do that?
I prune lavenders in early spring and after flowering. So now it is time to prune. The more plants you have, the more important it becomes to prune hygienically. But how to do that?