Update: I finally got the opening clear by using a rod (slightly larger & stronger than a coat hanger) purchased at Lowes. Had to tap it through the blockage, not sure what was actually clogging the hole, but I kept getting a reddish brown residue, guessing it was like a gummed up varnish. But, all is good now, wanted to thank the board for their input!
 

My bad you knocked off the strainer from within the tank!  I hate to admit this but trigger has made a bit is sense for a change..........but use a piece of inner speedo cable if you can, just like roto rooter!

Not sure I understand this now? You managed to get a wire up the outlet to knock off the strainer but still can't get air through the tube?

get a regular wire, attach the end of it to a drill and stick the other end to the hole, slowly turn the drill on, the wire will slowly unclog whatever's inside the tubing, might be some hardened varnish and gunk.
it will take forever to unclog it with thinner., you need physical force,not chemical force.

Gas tank clogged update:
I used a wooden dowel rod and pushed the strainer/filter off the metal tube within the tank. The strainer was actually in great shape. I still can not run a wire up through this 1/8" tube or blow air through it either, it is hitting something. Currently, I have the tube filled with thinner, hoping to dissolve or soften the blockage to get a wire through.

Doug's advice is absolutely right if all you need to do is clean the tank. In my case, I needed to re-seal my tank with the POR-15 system, which coats the inside of the tank. It will also permanently coat and seal the screen, so mine had to come out. With this coating system, however, the issue of the inside of the tank rusting is eliminated, so the chance of clogging is also greatly reduced. The screen in my tank was and is actually like new - not clogged or coated in fuel deposit.

Leave the pickup tube strainer if you can.

Paint stripper works better than lacquer thinner at dissolving old fuel.  My advice is to put 1/2 gallon of strong (not eco friendly) paint stripper in the tank along with a handful of old nuts and bolts, gravel, or even chain.  Slosh the tank every few hours and let the tank sit with the strainer in the stripper.  Be sure to at least stuff a rag in the filler neck to keep the fumes inside the tank.  After a day or two with the paint stripper, pour that out, rinse the tank, and replace it with a strong caustic cleaner.  You can use Draino as you suggest but I recommend Zep purple industrial degreaser available from your local home center. Put in about a quart of that along with a quart of water... leave the nuts/bolts/rocks/chain in the tank and slosh that like you did the stripper.  After another day, rinse the tank with clean water, remove the rocks, and blow the inside of the tank dry.

The little strainer on the pickup tube is somewhat important.  I removed one from my LH tank and later regretted it when debris plugged the tube.  It's heck trying to put a similar strainer back in the tank.

Mine came out easily just by pushing with a rod through the fuel line.

You can usually blow old tank filters off with enough air pressure. Whatever way you can i would get rid of it and just install a filter in the line somewhere.

71 mini, 

I have what appears to be a clogged gas tank. I removed the tank when I wasn't getting any fuel out the bottom. I have everything apart and can run a wire up into the tank through a small tube that ends with what appears to be a filter at the bottom. The filter looks to be metal and permanently affixed to the tube. Currently, I have this filter submerged in lacquer thinner, hoping to dissolve what may be old gas. Even used an air hose to blow air into the tank, trying to dislodge the clog. My next course will be to use drano. The overall condition of the tank, inside and out looks excellent.