Cast Iron Sediment Bulb Maintenance.....

[leo]

I've installed one of these in my early 1930 coupe because I believe it was what was there originally but also because I found the glass bulb type troublesome when it came to obtaining a leakproof seal. Can someone point out the maintenance for one of these? I cannot find anything in print about them. I'm assuming that the x shaped handle on the bottom is for clean out purposes........how offen? When?