> Q1: What is the easiest way to delete all the (say) .o files under all
> the sub-directories?

find . -name "*.o" -print | xargs rm -f

> Q2: What is the easiest way to delete all the files under all the
> sub-directories that are not write protected?

rm -r directoryname 2>/dev/null

documented on: 07-31-99