[Shop-talk] Probably a thing everyone already knew, except me, kitchen sink division

[David Scheidt]

the PVC pipe used for most residential sink traps is not-quite-opaque.
So if you shine a bright enough light (the 100ish lumen flashlight I
carry in my pocket is good enough) on it, you can see inside, and
quickly decide if the reason your sink is slow is because the trap is
full of crud, or the line after it is slow, or that your venting is
sub par.

-- 
David Scheidt
dmscheidt at gmail.com