Soapy water is recommended for outdoor tables such as yours, Ric....and a soft brush if needed.....then buff it as dry as you can....a windy day would be ideal.......x
If the table has been out in the rain, a mild solution of warm water and soda crystals will remove the residue and bring it up nicely. Dissolve a handful in a bucket or warm water and rub on with a sponge or a scrubbing brush depending on the state of the table.