The UGG brand makes a conditioner/cleaner for the sheepskin on your UGGs. You'll have to buy that and follow the instructions to clean them properly. DO NOT put them in the washing machine. That will just ruin them further.
I don't know if Uggs have special cleaning rules, but I would check out a Tide-to-go pen and see if it is safe to use on Uggs. That thing gets out lots of stains.
mr clean magic erasor
Use a mr clean magic eraser.
tattoos or pen marks
oxiclean!!
No, the marks made by a counterfeit detection pen will not disappear. The pen uses a special type of ink that reacts with the paper to determine if a bill is genuine or counterfeit.
eucalyptus
Stain stick
An ink pen, even the permanent type, can't leave permanent marks on the skin with normal use; no matter how dark you make the mark it'll wash off eventually.
The Pictogram Pen is a fabric marking pen. I am not sure who manufactures the pen. It has purple ink which either disappears over time or needs to be washed off lightly with plain water. It is used to place centering marks on fabrics to be embroidered and/or draw pictures on fabric that will be sewn on with a sewing machine.
with oxi clean
it makes marks