Yes, wipe the Betadine off with tap water before you roll but leave it for about three minutes on your skin to get the effect. It will not penetrate the skin, don't worry.
To disinfect a dermaroller, use about 70% ethanol (ethyl alcohol) or a mixture of ethanol and up to 45% isopropyl alcohol (we have a customer who soaked her dermaroller in 80% isopropyl and her dermaroller partially fell apart). I soaked mine for several days in ethanol with 30% isopropyl and it was fine.
Some tips on where to buy:
https://http://forums.owndoc.com/dermarolling-microneedling/can39t-find-proper-disinfection-alcohol/ 90% ethanol is not so suitable for skin disinfection because it evaporates too quickly off the skin so it doesn't have time enough to effectively disinfect.
Also, alcohols are most effective for disinfection when combined with water to facilitate diffusion through the cell membrane - 100% alcohol typically denatures only external membrane proteins. This applies both to disinfecting the skin and the dermaroller.
If you buy ethanol that is much stronger than 70%, just dilute it with tap water to around 70-80%.
Denatured alcohol is ethanol that has additives to make it unsuitable for drinking. One of the common additives to make ethanol undrinkable is adding methanol - methylated spirits. Nevertheless not all denatured alcohols are suitable for skin disinfection or even for dermaroller disinfection.
I paste here a reply from an expert:
Question:
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what is the difference between denatured alcohol and rubbing alcohol?
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Reply:
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Denatured alcohol is ethanol to which poisonous and foul-tasting chamicals
have been added to make it unfit for drinking. There is more than one recipe
for denaturing alcohol; some add methanol or isopropanol, some gasoline, and
so on.
Rubbing alcohol is an alcohol intended to be rubbed on the skin. Frequently
70% iso-propyl alcohol / 30% water is used; sometimes ethanol with added
iso-propyl alcohol is used. You don't want to use denatured alcohol that is
made with anything that shouldn't be placed on the skin, such as gasoline!
So, some, but not all, kinds of denatured alcohol can be used as rubbing
alcohol. Rubbing alcohol may also not contain any ethanol at all, which
would disqualify it from being "denatured". So, some but not all kinds of
rubbing alcohol are denatured alcohol, and some but not all kinds of
denatured alcohol can be rubbing alcohol.
Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois