Kevin,
I've used Goo Gone, a citrus oil-based degreaser and degunker, indoors. It's supposed to have petroleum distillates but it doesn't emit the fumes like pure petroleum-based solvents do like kerosene or naphtha. It has a pleasant smell. I use it to dissolve old grease, oil and adhesives. It works very well. I have purchased it in small quantities in the household sections of grocery stores and drug stores. Maybe another reader knows how to buy it in bulk, cheaper and in greater quantity for your parts washer.
Regards,
Carl Gonzalez
Bay Village, OH