Beware if you choose Whink Rust Stain Remover, available at most hardware stores.
WARNING!! The active ingredient in this product is 1%-2.5% strength
hydrofluoric acid. Look it up first. It needs to be used with caution. Long sleeves, rubber gloves, and safety glasses. Keep it out of reach of children and pets.
I believe this to be one of the more dangerous consumer cleaning products on the shelves. The molecules of this acid will pass directly through your skin and remain in your body like a heavy metal.
Here is a link to the safety sheet. Those safety warnings are pretty serious if you look up what they mean. The skull and crossbones on the bottle should be a good indicator.
I’ve soaked specimens in a ceramic bowl of Whink for several days. It will dissolve all the rust and eventually all of the host rock as well. The quartz will turn a chalky white. The gold specimen then needs to be neutralized and rinsed so as to avoid secondary contamination from folks handling it.