Deleting columns/fields from polygon shapefile attribute table?

• Use ArcToolbox > Data Management Tools > Fields > Delete Field.
• Choose your shapefile as the Input Table.
• Use the Select All button, then unselect the field(s) you want to keep.
• Hit OK.

ArcGIS 10 running on a 64 bit OS has a bug whereby you cannot delete columns using the right-click > delete field operation. Should be fixed in SP1 (I hope).

Deleting the fields is scary way of going about this. Are you absolutely sure you'll never need them? There are several non-destructive ways to accomplish your goal. One is to:

• load the shapefile and new table in ArcMap,
• join them on the ID field,
• right click the layer and choose Properties,
• on the Fields tab deselect all of the fields of the shapefile and click OK,
• right click the layer and export the data to a new file.

Only the checked fields will be exported to the new file and the old file will be preserved.