Toro 30410 Operator's Manual page 58

The muffler may be hot and could cause
injury.
Be careful while working around the
muffler.
2. Start the engine. Plug the normal muffler exit
with a block of wood or metal plate so that the
exhaust flow will be forced out of the clean-out
port. Continue to block the exit until carbon
deposits cease coming out of the port.
Do not stand in line with the clean-out
port.
Always wear safety glasses.
3. Stop the engine and replace the pipe plug.
58