Bright Tin Plate Question 1

[joblasso]

Hi everyone - this is my first foray on eng-tips and I cannot believe I have been working in a manufacturing atmosphere for more than 8 years and never came across this site. I do mainly purchasing / buying at my company, but because we are a small family run"job shop" in America we all do what needs to be done in order to survive and succeed in a fast fading profession.
Here is my question:
We do a job for a customer of ours that requires Bright Tin Plate over copper components we make. We recently ran a very small batch for an order placed. We had 2 units in stock and needed to make 2 more to fulfill our customers PO. We sent the new parts out to our usual plater for the bright tin... got them back, and when we did our QC control on all 4 units we immediately saw the the 2 pcs from stock (which the same plater did for us a year ago) looked like they had turned dull or faded (for lack of a better or more technical way to describe it). I know for a fact that the parts were bright as shiny silver when they were put into stock.
We contacted our plater about why they would fade and they told us that the paper we used caused the fading. Is this possible?? I find it hard to believe because there was dulling all over the parts, not just the surfaces that were in contact with the tissue paper we used to wrap. I then proceeded to pull out several other items we have in stock that are copper with bright tin plate from various times in the past and they look fine.
Our job at the shop is to fabricate. We rely on our vendors to do their job (plating, painting, etc).
Any help or input on this would be greatly appreciated!!
If specific drawing spec is needed to answer, please let me know and I will pull it up.
Thanks again!

 

[Compositepro]

Tin, like silver, will tarnish easily unless kept in a very clean and dry environment. Most paper contains moisture and other corrosive ingredients. But the paper is only one possible cause. A lacquer coting can help.

 

[joblasso]

Compositepro - THANK YOU!. I will certainly look into this when I get to the shop in the morning. Really appreciate it.

 

[ornerynorsk]

Paper has sulphate (ite?) compounds used in its manufacture which will cause smutting or oxidation. If a paper wrap is necessary, VCI paper might be more appropriate.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.