The problem is getting whatever is put in there back out. If there's a big access hole somewhere like the one for the sending unit, no problem. How about what gets trapped behind baffles where there's no easy access? I like to use small things like BB's, or 1/4" nuts, etc. that can be retrieved with a magnet. Mix up a strong solution of water-soluble parts cleaner soap. Fill the tank halfway with water, and strap it down in the bed of a pickup. Drive around for about a week. The sloshing action of the half-full tank and the normal agitation of bumps and corners will do the agitation for you.
Jerry
