Dataflow date with 00/00/0000

In a dataflow I am creating, I ran into the error: "We couldn't parse the input provided as a Date value. Details 00/00/0000".  Looking at the incoming csv file, this is coming from a DOB (Date of birth) column, where some have data.  I am assuming data entry is made this way when the birthdate is unknown.  What would be a good way to handle this?  Is it a simple search and replace (with something like '01/01/1900')?