==== Show non-default parameters ====
 <code>
set pages 100
set lines 100
select name ||'='||decode(type, 2, **')||value||decode(type, 2, **') parameter
from   v$parameter
where  1=1
and    isdefault = 'FALSE'
and    value     is not null
order  by name;
</code>
==== Reset/Unset a spfile parameter ====
<code>
 alter system reset <parameter> scope=spfile sid='*'