I use
this pump to clean kegs.
I've used it with a PVC tee like I've seen in this thread for a couple years now, along with two connections for a Corny keg. Sometimes I'll need to use a brush afterwards, but generally it gets it pretty clean.
You can use Oxiclean or Oxiclean + TSP 90 (knockoff PBW) in the cleaner but you'll need to use some baby gas drops or Fermcap (both are Simethicone). That'll reduce the amount of foaming from the Oxiclean.
I've only had a small container of PBW, and it foamed up just as bad as Oxiclean for me.