zarck wrote:

Acids as vinegar will also tend to etch the metal.

While I'm sure this is true of concentrated vinegar the cleaning vinegar I use (schoonmaakazijn) is only 5% to 10% concentration.

I find this especially handy for switches leaving them in the vinegar for about 30 minutes. Then I take them apart and clean them in water with a brush.

@Troepfler, are you using magnets in the SMPL switch? I've made SS springs for mine which imo improve conductivity.