90% Isopropyl Alcohol for Cleaning Coins

So I'm sure this question has been asked and answered many times...but using the search function I haven't been able to find specific answers I'm looking for. Google search is similarly not returning specific answers. I'm a novice so forgive me for clogging the forums with a simple question like this.

Is it advisable to soak coins in 90% iso alcohol to remove skin oils/fingerprints? How about to just remove "gunk" from circulated coins?

I understand that copper reacts differently than other metals, and specifically in mind I have a bunch of NIFC Kennedy halves, some of which have minor fingerprints/oils showing, and then just random circulated US coinage (all denominations) with oils/"gunk" etc. I also have a stack of BU Austrian Philharmonics, and a friend of mine fingered one up not knowing how to handle coins properly, so it now has fingerprints/oils on it. I happen to have a bottle of 90% iso alcohol in the bathroom, so I'm wondering if this stuff does the trick to remove minor stuff like what I'm describing.

Feedback much appreciated!

Edit: I will check back later for answers, not ignoring anybody

 

Log in or Sign up to hide this ad.

It shouldn't hurt. It won't remove prints unless they're very fresh as in just a minute ago. I've even soaked coins in Everclear. If you do that, just don't drink it after.

 

If it were me, I'd go with acetone because acetone's vapor pressure is a lot higher than isopropyl alcohol's, meaning acetone should evaporate off of the coin a lot faster and be easier to work with.

 

Alcohol is a polar solvent which won't harm a coin but acetone is better at the same jobs.

 

Thank you for the replies guys, I will check out that other thread and probably go out and buy some acetone. I've been having a good old time roll hunting and just looking everything up, it's really helping me to learn about each modern denomination...and now I have a big pile of cheap and dirty coins to experiment on.

 

I sometimes use rubbing alcohol. One thing you should be aware of is that it will sometimes leave a light white-ish haze on the surface. This is not due to the alcohol itself, but the water content mixed in with it.
In true Russian fashion, I've used pure ethanol (drinking alcohol) to better effect (not what you're thinking).

 

I mostly stick with acetone. Verdicare works good on copper used denatured alcohol in the past too tho with no adverse effects. But can leave a film on the coin

 

Verdicare is supposed to leave something on the coin, to protect it into the future. I have seen enough Verdicare-treated coins in slabs to know the TPG's don't object to whatever Thad is using for ingredients. If alcohol leaves a film on the coin, it's either because the alcohol or mixed water was insufficiently pure, or whatever it picked up from the coin didn't rinse off and got redeposited. You should be happy with both substances used in conservation.

 

If you object to the film left by verdicare acetone removes it. When I had a film from alcohol it was usually crud from the coin and a second rinse or a quick acetone rice removed it. I prefer acetone for its fast evaporation rate tho

 

Yeah, acetone's extreme volatility makes it the ideal final rinse. I couldn't imagine putting a coin away without a final acetone rinse. Of course, this being the Internet I should offer the caveat that there are some coins which oughtn't even be touched with acetone....

 

I've had aluminum-bronze coins that turned weird color hues after being treated with acetone.

 

Where does electrolysis fall (baking soda water solution with aluminum)

 

It characterizes as "advanced technique requiring care that side effects do not themselves affect the coin, while offering a powerful tool for specific corrections."

Something else had to be involved. The fact that acetone cannot have that effect is plain science. Acetone isn't really into oxidation; that's why it works so well for us.

 

Yea I'm sure it was something on the surface. I've had this happen specifically with Danish 1 and 2 Kroner coins from the 1920's to 1960's. Perhaps the planchets were treated with something that reacts with the acetone.

 

I use 90% alcohol to remove tape glue. It is the only thing that works if someone wraps coins in packing tape. Best to ship them back when they do that but sometimes it don't matter when the coins were bought at melt.

 

I know that concentrated isopropyl alcohol will "melt" plastic so keep that in mind when using it.
Even rubbing alcohol (76% isopropyl) will harm plastic is used too long.

 

There isn't much that's capable of reacting chemically with acetone; it's used as a cleaning agent for aluminum, for instance. It does make one wonder what the Danish used for planchet prep on them. You've been doing this too long to just mistake a correlation. Have some images? I'd like to think further about this.

That is acetone's main use, along with handling PVC contamination - removing adhesive from coins.

 

I understand that household ammonia followed by acetone works well on silver coins - can't speak to copper.