The large TotalBoat epoxy metering pump dispensers include the TotalBoat High Performance 2:1 epoxy system metering pump and the MakerPoxy (1:1) metering pump. These pumps have separate reservoirs for the epoxy resin and hardener components.
To flush and clean these pumps, begin by pumping any remaining epoxy resin or hardener from the reservoirs. To clean the insides of the reservoirs, use denatured alcohol. You do not need to run denatured alcohol through the pump. To clean the spouts, remove them and soak them in denatured alcohol. If desired (though usually not necessary - even if switching epoxy systems of the same mix ratio), you can take apart and clean the pump with denatured alcohol, then reassemble it.
After the resin and hardener reservoirs are clean and dry, fill them with epoxy resin and hardener that is the appropriate mix ratio for the particular pump. Once filled, prime the pumps before use.