The best way to try and get rid of the portable toilets from the out of business company that owns them is to write the contact person a letter stating that he or she has 30 days to remove them from the property that they are on, and if not remove dduring this time period you will deem them abandoned and do whatever necessary to dispose of them.Keep a copy of the letter for future reference and need. If the 30 day time period comes and goes with nothing happening, then you do what you need to do to get the items removed from where they are located.