If it is efflorescence, use a cleaner labeled to remove that. Muriatic acid
will work but probably too aggressively.

If it is a surface contaminant like dirt, use a power washer with concrete
detergent


"kay7777@post to group" wrote in message
...
How do I get the white marks off of the concrete near my house......It has
happened after all the rain we have had....Thank you for your help...k