I've bought quite a few coins recently that turned out to have BD, unfortunate but guess its inevitable with the climate in the UK and most of Europe.
I don't know if it can ever be completely stopped but do think the progress can be slowed to the point where we'll all be dead before any further actions are needed.
I personally still don't think its fully understood but moisture (perhaps not a cause) is certainly a catalyst and needs to be addressed.
I soak the coin in distilled or de-ionised water, any pure water will do, the purer the better. Essentially you are trying to dilute and draw out of the coin the minerals that started the process off. If the liquid you are using has minerals in it (tap water) you could make the coin worse.
I also use dental tools (£5 from
ebay) to gently pick away at the affected areas on the coins surface, its a slow process and its best to do it for an hour or so then pop the coin back into the distilled water for 24 hours and keep repeating.
Every time you take the coin out you will see new areas that need attention - keep going till all of these areas are gone. Try to use downward pressure on the BD but if this does not work use small circular scrapping motions and keep the coin wet, not sure why but this seems to minimise scratches. Sometimes its easy to remove but other times very difficult.
Some people then soak the coins for months changing the water regularly - I guess every coin will be different but not sure how you can make this decision, I know some people PH test the water but this seems a bit over the top to me.
Once I'm done soaking I also pop them in the oven and Ren wax them while still hot, this prevents the moisture from getting straight back into the coin and restarting the whole process. Like most people I also keep Silica gel in my coin box.
Its something that has worked well for me so far but who knows what the coins will be like in 10 years time. Collectors are also split on the use of Ren wax, I like it, certainly when a coin needs treating but some of the purists will not buy a coin that has had it applied. I guess its personal choice, it is not as hard to remove as many people say, at least 90% of it isn't. I don't intend to resell the coins I wax so its irrelevant to me and an issue easier to just ignore.
Sometimes you have to be hard with the coin and 'damage' it slightly to clear all of the BD, difficult but better than just leaving the coin to slowly crumble away. Here is a thread with a coin that I cleaned of BD but had to strip it back to the metal in places.
www.coincommunity.com/forum/...PIC_ID=100564
Posted 12/02/2011 05:13 am
