Tungsten is very resistive to acids, silver in HCl passivates, the high oxidizer can help to react with the tungsten, and the silver crust can be broken loose with vigorous stirring and knocking it around with a glass stir rod, if this is tungsten and silver it will not be fast or easy.
Do you have pictures or information where the contacts came from?
You may find this useful:
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=58&t=16364
Sometimes you can get data sheets for specifications with a search, of the relay or other switching device there are some good posts listing metal used in switch's and breakers, allot of these contain mostly silver, I can not tell you what the Westinghouse or other brands of breaker’s, or switch points you have contains, but my guess is mostly silver, and that is the way I feel you should purchase them as silver, and also these can be a cost you in time and reagents so figure that also. Switches can contain gold or gold plating, but that is usually for low current and high reliability in switching like for digital electronics, large current devices will usually have tungsten.
Here are a few metals you may find in switches. Relays and circuit breakers:
Silver usually predominant metal
Group1: Ag-Mo, Ag-Cu, Ag-Cd, Ag-Fe, AG-Ni, AG-Wc, Ag-C
Group2: Ag-Cu-Ni, Ag-Cd-Ni, Ag-Ni-Mg, Ag-Fe-Cu, Ag-CdO
Group3: Ag-A, Ag-Pt, Ag-Pd,
Group4: Cu-W, Cu-Wc
Some will also contain PGM metals.
Metals to look for: Au, Pt, In, Rh, Ir, Os, Ag, Hg, Pb, Cu, NI, Fe, Co, A, Cd, Mo, SN, Mg, W, C, Zn, and oxides of metals
Tungsten melts about 3380 deg C which makes melting difficult
There are spring materials made from copper, stainless steel, beryllium, bronze and kovar
Relay contact point's, switch's, circuit breakers and the like, will usually contain other metals, some of higher value than just the silver.
And if contacts were Russian, I would surely check for platinum group metals.
Gold flashed, or plated, silver, gold overlay base metals, silver nickel, silver cadmium oxide, silver tin indium, silver copper nickel, gold silver nickel, gold silver nickel palladium tungsten.
Some of the metals to watch for, Au, Pt, Pd, Ir, Rh, In, Os, Ag, Ni, Cu, Fe, Co, A, Cd, Mo, Sn, Pb, Hg, Mg, W, C, Zn, and oxides of metals.
Tungsten (W) usually used in high current type, (waffle back), high melting point 3380 deg C, this can make melting difficult, not easily dissolved, hot HCl with concentrated H2O2 will attack.
Tungsten silver contacts, in a (50% : 50%) solution of 70% HNO3 : H2O, heated can dissolve the silver out, leaving a porous shell of tungsten, that can be broken or crushed, when silver is removed. (note added with edit)
The metals or combinations of metals, used are usually dependent on the purpose and use of the contact points (relay, breaker, switch, etcetera), the voltage, current, environment, inductance or capacitance in circuit, Arcing, welding, oxidation, pitting, inrush current, contact bouncing, whether AC or DC application,
Well lets just say there are many factors that come into play when a contact point is used in electronics or electrical applications, and these little buttons of metals are in most all electronic and electrical devices.
Melting contacts can produce deadly fumes cadmium and zinc as well as other volatile metal toxic fumes and floating oxidized particles of the metals easily breathed into the lungs.
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