Here is the particular verse in question -
Mark 7:4 And when they come from the market, except they wash, they eat not. And many other things there be, which they have received to hold, as the washing of cups, and pots, brasen vessels, and of tables.
That was the KJV translation. Here is Young's literal translation -
Mark 7:4 and, [coming] from the market-place, if they do not baptize themselves, they do not eat; and many other things there are that they received to hold, baptisms of cups, and pots, and brazen vessels, and couches.
The Greek word translated for wash and washing in the KJV is actually baptizo, as Mr. Young has literally translated it. From you said, apparently folks were taking their tables or couches (couches is more literal) to the nearest available large body of water and immersing them in order to clean them.
I don't know about you, but I have never met anyone hauling out their couches (or tables) to the local swimming pool or church baptistery in order to wash them.