Siebel Tools >  Find all Business Components that use a Column in a Table

Find how many Business Components use a table column

 You can find out how many business components use a Column from Siebel Tools -> Flat view -> Field 

Enter the Column name, check that it is Active (Inactive = not checked).

I use Siebel Power Communications or Siebel Call Center mostly so you can use the SQL below to remove Projects that belong to Financial Services or Auto or Medical.

select distinct b.name , c.name

from siebel.s_field a, siebel.s_buscomp b , siebel.s_project c

where a.col_name = 'ACT_CLOSE_DT'

and b.table_name = 'S_SRV_REQ'

and a.repository_id = '1-29C0-1'

and b.name not like 'eAuto%'

and b.name not like 'FIN%'

and b.name not like 'Medical%'

and c.name not like 'FIN%'

and c.name not like 'eAuto%'

and c.name not like 'Medical%'

and a.INACTIVE_FLG ='N'

and b.inactive_flg = 'N'

and b.row_id = a.BUSCOMP_ID

and b.project_id = c.ROW_ID;