Hi ams162,
As jopar states, it is not advisable to use alcohol based gels as they do impede on bg results, I was told this by my diabetes nurse just recently.
I try and wash whenever possible, but if I can't I use bottled water and a tissue to dry, failing that if my hands are relatively clean and I haven't been handling any sweet stuff, I just test away. As you are asking advice with regards to your child, I would try and carry a small bottle of water to prevent infection, but just the same remember to change the lancet each time you use the finger pricking device.
Nigel