Chemical Here is the answer to solder removal.

[jungle_Dave]

I did add another 40 ml of 12% H2O2 on day 3 as the reaction died down. That's also when it turned yellow. Got to test it!

 

[jungle_Dave]

Perhaps you did use too much and too strong H2O2. It is a strong oxidizer and that may be the case that it help to dissolve your gold?

Spot on!
Just to test I did a crude experiment.
Added 10 ml of 2% H2SO4 to the first filtrate,agitated and let settle 24 hours.
I have a spiderweb matrix of inpure metailc gold on the bottom of the flask.

I oxidized the gold into solution or micro particulated
How cool is that!

Back to the original post. ..
I used an excess of H2O2 at 12% and it oxidized gold.
30 % H2O2 would for sure.
That's a risk.
I'm waiting on new sncl but I'm saving everything filtrate solution and control sample.