Can't get gas into the tank, acts like it is full, but it is empty

if these old cars have sat for some number of years, first thing to do is PULL the tank, clean it, replace or clean and check the fuel pickup/sender, and check tank for any pinholes while out. yes pinholes! clean/replace the ground strap at the pickup, if an original 71 tank, it would have a vent nipple at inside top side of tank and rubber hose to the vent tube located in trunk. 3 other rubber hoses there at that tube. dirt daubbers?????/
and you cold have a dead Iwegian corn mole dead in the filler hole!