[QUOTE=Duck Duck Goose]
You can also flush them if for some reason the handle and/or tank mechanism isn’t working (or if your water is shut off due to plumbers working downstairs). Just dump in a couple gallons of water all at once (a 5 gallon pickle bucket works well for this).
Of course, this means you would have had to put by a bucket of water before the plumbers shut off the water, but no system is perfect. 
[/QUOTE]
Also, plumbers tend to frown on this practice when they’re downstairs working on your sewer line.