how to VALIDATE INDEXTYPE and OPERATOR

in MDSYS schema I have invalidated two operators and one indextype. Anyone knows how to VALIDATE(recompile?) then?

Oracle version 8.1.6

ALTER OPERATOR your_operator COMPILE;
ALTER INDEXTYPE your_indextype COMPILE;

thanks, akkerend.
That's simply amazing. Those commands are not documented in 816 doc set I have...