figured id give a little lesson to those who may not know Many years ago I started stacking silver. I didn't have alot and among my first purchases were 5 oz bars and this 1 ten ounce bar They were all in plastic wrapping from the major distributors so I figured "heck, ill just bundle them together with a rubber band" Poor choice. After a few weeks or maybe a month (and stored in a cool, dry closet) i get these gnarly black tarnish marks on them I dont know the science behind it or even how it tarnished through the plastic, but keep rubber bands the hell away from coins, bars, what have you
Interesting. I think you're right about the rubberband. Look at those marks! I have large bars stored in their plastic, and they still look great.
In 1839 Goodyear discovered by accident that rubber when combined with lead and sulfur make the natural rubber more ply able and increase its usage. Prior to that rubber was to soft in the summer months and to brittle in the winter. In 1841 rubber bands were invented and today they have many uses. The Post Office is the largest consumer of rubber bands. Even the food industry uses them. Because the rubber is combined with lead and sulfur it is not to be used with metals. It will permanently stain them, even through plastic. The stain can be removed but all luster is also removed, hence the everlasting stain.
The sulfur will not just stain metals . . . it corrodes them. I recall an issue with leakage on submarines because of the sulfur-induced corrosion of the seating surfaces for breech door seals on torpedo tubes.
This may be a dumb question but with bullion does staining even matter ie: paying for mineral weight not “eye appeal” or luster, etc? Mind you with my collector OCD this would drive me nuts, but value wise does it matter? Do people collect certain silver bar designs?
I found that out storing silver coins in those soft PVC flips rubberbanded together in batches. In just a year or something they had black marks on it. I have a thread about it especially in relation to a 1922 Peace Dollar that had black marks on it. I replaced those PVC flips with non-PVC flips and haven't had a problem since even though I still use rubberbands.
Some people collect silver art bars. They want the silver to look as good as a coin to a coin collector.
Disconcerting to say the least..... I have my slabbed coins grouped together and have the slabs rubber banded together in my safe. I doubt that the sulfur would leach through the TPG slabs.... But then again I wouldn't think it would leach through a PVC wrapper either. I'll be removing the rubber bands from my slabs tonight.
The sulfur is not likely pure, but an acidic compound that is interacting with the latex of the rubber mix. Add a little moisture and it is fairly corrosive.
If you were buying silver with big black streaks on it, or would you rather have nice lustrous silver without black streaks? Would you pay the same price for both, or would you want the streaked pieces at a discount? Yes, it does matter.
The sulfide will go right through the plastic, which is porous. It will also go right through the hard plastic of slabs, so don't ever put rubber or elastic bands around coins to hold them together. I am even afraid to put the rubber band around coins when submitting them for grading in-person.
