Whats the best way to clean {soak} a gas sending unit in a 1956 buick wagon

I dropped the gas tank in my 1956 buick station wagon thats been in storage some 20 years and drained the old gas out .The tank is surprising clean just dirty gas.So i will flush it out .The sending unit pick up tube has some rust on it.Is there something i can soak it in to clean it up? Thanks Bruce.

 

In my opinion I would just get a new one. I personally wouldnt risk it. Sorry but I cant remember where I saw them for sale. I think rareparts.com might be where though. I stopped working on my 57 2 1/2 years ago but Iam gonna get back into it now that the evil other half is gone.
Hey guy ive never seen a 56 buick wagon..even in a picture. Ive only seen 57 wagons in pictures. Can I see a pic of it? oh btw; I have a 57 special 4 dr hardtop project car and a 57 4dr sedan for parts.

 

Put it in the DISHWASHER!!! I couldn't help myself.

 

White vinegar. Or buy the Marine cleaner used by POR 15 in their gas tank cleaning/sealing kit.

 

The Marine Cleaner really works. I should have taken before/after pics of my sender. What was left after that treatment brushed off with my fingers.