Tin plate v silver plate for solderable terminals

We currently supply a range of terminals tin plated over nickel and the base material is brass, we currently experience a drop out rate over time due to deterioration and these will not solder. would silver plate eliminate this issue and is the best way forward.

For solderability, use matte tin with no brighteners or very little. A stearic acid ⇦ on eBay or Amazon [affil link] treatment will help a lot. Storage conditions make a big difference. Some plastic bags promote corrosion. You can also fill the bags with nitrogen or helium, purge, refill and seal for better storage. Silver will last longer, but is it worth the tarnish and the cost? It also needs to be matte.