Don't do it!
I asked my husband to help me wash the 78 one day and his way was MUCH faster!
I used to use a small kitchen sponge (with no scrubber side, just sponge). It was small and fit my hand.
However, Kenny grabbed a cotton towel, about the size of a large hand towel...and I found I could wash the vette in about 10 minutes!
Flop the towel over the top, so it spreads out and covers a large area. I wash the top, back glass, back deck, side windows, windshield and hood. Resoak the towel about 2-3 times during this procedure. (If the vette is really dirty, keep a clear bucket to 'rinse' the towel in and then reload with suds from the wash bucket)
Next I run around above the 'mid-line' with the towel wadded up between my hands, and using my fingers to press the towel to make contact, I can be sure I've gotten everywhere. Scrub the front good, for the bugs, get around the mirrors and wash inside the taillight indents.
Next-to-last I do below the mid-line, which seems to catch the most dirt. Doing this last also assures you aren't spreading 'grit' from top to bottom if you wash the car 'quarter-section' at a time. I'm sure to scrub good in the 'gill' area and get the rocker panel(?) below the door.
Last, I wash the wheels and tires.
I run up onto the hwy as fast as I dare and turn around and come back at the first exit. Towel off any remaining water, usually just a few beads around the ttops and inside the taillight housings. If the headlights are up, there's usually more beads of water on the hood.
In the time it took me to type this, I could have washed 78 twice!
Silver
ps...this is basically just a touch-up wash between serious washings prior to waxing.