Here's how to successfully preserve soapnuts liquid:
You will need resealable and sterlized quart jars and soapnut shells.
Place the equivalent of 7-10 soapnuts in each jar. (It's better to use smaller soapnut pieces). Fill with boiling water but leave a 1/2 inch space at the top. Place the lid on securely.
PRESSURE COOKER: Place the jars in the canner, and process according to manufacturer's instructions for 15 minutes at 10lbs of pressure.
Use only canning jars if you use this method.
WATER BATH: Place the filled jars in a large pot of boiling water. Make sure to cover the jar completely. Bring to a rolling boil and set the timer for 30 minutes. Remove jar from boiling water and let cool.
OVEN METHOD: Preheat the oven to 250F. Place 7-10 soapnuts in a clean glass quart jar with a resealable lid. Fill with boiling water but leave 1/2 inch at the top. Place lid on securely. Watch until the liquid starts to bubble and then time it for 30 minutes.Turn off oven and let cool a little. Remove from oven.