Winterizing question (toilet and black tank flush)

[martyperu]

Is it a good idea to put about a cup of antifreeze in toilet bowl for the winter storage to prevent seal from drying out and then leaking? In the past I have just sprayed silicon spray the best I could on seal for winter.
Does the blank tank flush drain or should I make sure antifreeze is run through the flush lines.
Thanks

[Waricha]

I normally leave about a cup of antifreeze in the toilet I'm not sure if the seal will get damaged if you don't so I do it anyway. As for the flush lines in the black tank, I blow them out with compressed air for about a minute or so and have never had a problem. I live in upstate NY where it does get well below zero and never had an issue in the spring.

[Rondo]

When winterizing I take an old tooth brush and carefully run it around the seal where the flapper closes on it. I do this on both the top and bottom side of the seal. This cleans out any possible solids or gunk that might have latched onto the seal. I then take the tooth brush and put some Vaseline or plumbers grease it and run it around the seal giving it a good coat both top and bottom. I then close the flapper and put about a cup or two of the pink stuff in the bowl to keep that seal from drying out even though the Vaseline or plumbers grease should solve that problem. Better safe than sorry I always say! I also blow the black tank flush line out with air to get any water out of it so it doesn't freeze.

[BB_TX]

I use antifreeze for winterizing. So when I run antifreeze thru the toilet line, it leave some antifreeze in the bowl.

And I do run antifreeze thru the black tank flush line. After running antifreeze thru the outside shower, I connect that shower hose to the black tank flush and use it to run antifreeze thru the black tank flush line. My black tank flush has a check valve behind the screen washer so it does not drain when disconnected.