Modifying a field in a SQL Table

If I have a field in a table that has

“456789 —Field Name (XYSKU)

How would I modify that entry to remove the quotation mark and keep the numbers? I would want this to update all entries in the associated field because all entries are preceded with (“).

I have the same problem with another field that has the quotation mark at the end of the data

000000765.00” –Field Name (COST)

Thanks in advance!