passing clob values to stored procedures

[zulu99]

Hi All

We have a stored procedure which takes a clob as input parameter in 817 database.
How do i assign a value to the clob column in a plsql block & call the stored procedure.

when i try to assign a value to a clob variable in a plsql block it gives the follwing error
PLS-00382: expression is of wrong type


Regrds
Sushant