Parts Washer cleaner

I rebuilt 2 trannys the last year. I only needed to clean the outside. If the parts inside need cleaning, something sounds really wrong and they are probably severely worn. I don't have a parts washer. I just use small brushes with gasoline or diesel. Actually a mixture left from when my wife called saying "the car sounds funny". I said "smells like gasoline, did you remember to fill it with the green hose?" (diesel engine). Nope, so I siphoned out 18 gal. Big parts I clean outside. Small parts on a table in the garage. I put newspaper underneath to catch everything and change it regularly. Diesel works better since it sits longer without evaporating. Of course, don't smoke (ever, even when you not working on cars).