rjchandler:I,m not sure how you would go about this
Just depress the purge when taking a breath.
The symptoms are the same whether it's the exhaust exhaust valve or the diaphragm that's fouled. A cracked housing or any kind of a leak in the second stage will also cause the reg to flood.
IMO, this is an example of a simple skill that I woldn't want to dive (solo or with a buddy) without. It's also a skill that most divers aren't introduced too until they begine technical training.
How many here do a negative pressure test on their regs before a dive?