here's what I think,
fist of all this is hard to answer because we may not be talking about the same thing.
first we need to get our language on the same page what do you call contacts?
now if you are calling fingers contacts this info may change, and rinsing them and using HCl/Bleach to dissolve and SMB to precipitate the gold. ferrous chloride or acid peroxide(copper chloride) great for recovery of these, I prefer acid peroxide, as it works really well and is lower in series.
or are you talking about contacts? I call switch points contacts.
there are many diferrent methods to attack recovery, and a few to refine,
if these are contacts not fingers, my idea so far you have just recovered some impure brown powder not pure gold.
even if these were gold foils they need refined.
contacts to me are switch's from relay's switch's breaker's etc...
they can contain several metal's including gold silver platinum group and many others also oxides of metals depending on the contacts working parimeters,using Iron chloride to remove copper is good but you will not be left with pure gold, even if the contact was only gold and copper which it most likely is not, gold is probably only there in small portions normally, and usually the silver will be in high portion, Iron chloride will not dissolve the silver gold, PGM, or lead if it is involved, also if much silver the ferrous chloride would have a hard time getting to the base metals to dissolve the copper etc, silver chloride would block them from the acid.
if the ferrous chloride made them to fine powders that would work to save chemicals (amount of nitric), also if it works to get them to powders what we call acid peroxide will work similar (HCL/H2O2) which we use to make copper chloride to etch with similar to your ferrous chloride.
these impure powders if they are powder, can have many metals besides gold, basically anything below Iron in reactivity series, and including iron, and possibly base metals that silver chloride protected,
now since you used a chloride (iron chloride) these powders are salts of chlorides.
(when you disolve a metal in an acid you get salt of the metal and the acid),
these chloride salts can not be added to nitric directly normally as this would form aqua regia, even week will dissolve your gold with the other base metals,
but if you heated these salts to a high enough temperature you will convert the metals and drive the (Acid portion ) out as gases in this case chlorine gas, we call this roasting or incenerating depending if we are talking ore or refining,
so incenerate your powders to drive off chlorine as gas, since you have gold I would under watch glass, start heat low till they become liquid crystals and most of chlorine is removed from chloride salts then raise the heat heating the metal powders to red hot, but not melting them back to metal.
now nitric can be used to remove base metals,dissolving silver, and Pd if any,(with lots of silver Pt likely to follow it here), you can recover silver and palladium with copper bar or other method, (treating silver in cell if you get bunches of it can recover pretty pure silver and anode slime can hold values)
the insoluble powders from the nitric treatment, would contain your gold possible PGM, and some silver and some base metals but not so much which would give much trouble.
these can be dissolved in Aqua Regia , or HCl/bleach, and gold precipitated from these, them PGM if any.
I know this sounds like alot and I have not went into any details, but this can give you Ideas
and will also give you something to look for, if I was new to this I would search through the forum or Hokes book reading into more of the details of these steps, It will seem overwhelming at first but soon it will all just fall into place, dont throw out any of your solutions or powders, they can have your values, a stock pot. is very important especially for beginners, you will refine it later and find how much more study you needed when you first started learning this,hokes is a good source for learning about stock pots and all of this.
(even if you have foils, studying these principles will only help.)
good luck
