Don't worry too much about that bit of liquid in the line. It's generally a by-product from the refining process, tiny droplets of oily stuff that fall out of suspension and wind up in the lowest points of your system: The bottom of the propane cylinder itself or at the lowest point in your lines, generally right where the rubber line from the regulator connects to the metal line in front.
If it's mercaptan, as some suppose, well, you'll know it fast. Mercaptan is really, really stinky stuff, a gas that is added to propane to identify a leak with your nose. Stick your finger in the oily substance. If your significant other will not allow your into the house afterwards, or if you find yourself fighting off clouds of black flies, then it's mercaptan (which is kind of hard to find in the regular atmosphere as a liquid!). Or you messed up and got nasty old rotten eggs on your finger instead.
Will it foul your regulator? Probably not. The tiny amount of it in suspension just goes right through the regulator. (Remember that you're drawing vaporous propane from the upper part of your RV cylinder, not liquid from the bottom.)
If you do wind up with a bit too much of it over a long time, you can just remove the rubber line from the metal line and drain it out, just as you did, TOPORANGER. But it's pretty unlikely that you'd ever get enough into that low point to stop it up. Possible, just not super likely. Definitely not one of those "yearly maintenance" matters.
Originally Posted by TOPORANGER
I just had one 30# aluminum tank in for re certification.
Took it to a long time family operated propane company in Cedarburg WI. Boehlke Bottled Gas Corp.
During removal of the main gas supply line, for tongue painting, I had found oil in the line. So I wanted the tank OPD valve removed and the tank inverted to remove any oil. I had gotten about 2 tablespoons out the gas line and about the same came out of the tank itself.
The Tech found that the OPD valve was in need of replacement. I was able watch as tech did the service and he explained everything completely.
They charged me $35 for the valve and $5 for the recert.
Engraved new recert date in tank and added a sticker to the inside of the handle ring with their business info and recert date.
$35 for valve, $5 for recert and $26.03 for propane fill
Will do the same to other tank when it is empty.
I just showed up at their location without an appointment , and 1/2 hour later I was out the door. Overall I was very pleased with the service and price.