Importing blank columns using "Replace" action does not result in deletion of attribute values. Magento 1.5, 1.7
E.g. a csv containing a list of skus whose sale end date has passed to try to delete those dates and sale prices from the db does not work.
sku | special_price | special_price_to_date MX300 | | MX301 | | MX302 | |
Blank columns do not effect any change. So how do I delete values for a product attribute using import?