I think The "Organic Castor Oil - Hexane Free & Certified" from the Heritage Store is safe to do castor oil flush. That was what I used long time ago. I do not use castor oil flush now any more. It's not because it's not safe but I do not need it any more.
I think my plumbing systems are functioning very well now. Thank God for all those cleansing regiments and helthy life style I followed religiously over the years paid off immensely.