I have a STB that I pulled with naptha until my yields were almost non existent. The STB was 500g of MHRB, based with lye. The soup has been sitting in the jug for a few months now, waiting for my lazy ass to order some fumaric acid. It is finally on its way. Should be here soon. I have some D-limonene and want to add it to the STB in preparation for the arrival of the fumaric acid. I was planning on transferring the gallon of soup into glass jars, bit by bit to do the limonene pulls. The STB was done in an HDPE2 jug.
A couple of questions:

Is there a formal tek for doing a FASA on a depleted STB?

Can I just add the D-limonene to the plastic jug and do the pulls out of it instead of doing multiple transfers of the caustic soup into glass? The D-limonene came in an HDPE2 container, so I'm thinking it's safe with plastic.

Should I heat the soup or just the D-limonene? Or, should i heat both?

How long should I let the pulls sit?

And finally: How much D-limonene should I use with a gallon of MHRB soup?

Thank you for your time and attention and your carefully considered responses. I don't care what anyone says, you people are great.

well, I've started without you. I have done 2 pulls with 100 ml of D-limonene on approx. 500 ml of basic mimosa soup previously depleted with naptha. I put about 200ml soup and 75ml of D-limo ea. in 8oz. ball jars and heated them in a water bath for about an hour and let them sit over night. I decanted the D-limo and performed the same procedure with it on 2 more jars of MHRB soup. My fumaric acid should be here today. Should I pull from more soup with this D-limonene? I'm hoping this will get it super-saturated. Is there a way to tell when it's getting saturated, like you can with naptha.
Speaking of which... I'm tired. I'm going to go take a nap(tha).