Deleting a million directories in Linux

This morning a component went ballistic and created more than a million folders under /path/to/myfolder, until the file system was completely full.
this command was showing 100% of Inodes used:
watch df -i /opt/oracle/domains/osbpr1do/shared/apps/fileadapter/controlDir/fileftp/controlFiles
You could delete folder/files in several way, most of them VERY inefficient:

#this takes forever and deletes also the parent folder
rm -rf /path/to/myfolder

#this funnily fails with "file not found", most likely because there are 
#special characters like a equal sign = in the folder name
find /path/to/myfolder -type d -mtime +5 -exec ls -ltr {} \;

#of course I have tried also with quotes, with same result
find /path/to/myfolder -type d -mtime +5 -exec ls -ltr "{}" \;

#I have tried deleting only subsets
rm -rf /opt/oracle/domains/osbpr1do/shared/apps/fileadapter/controlDir/fileftp/controlFiles/a*
#but the problem is that the shell expands the a*, and this can resolve to too many argumnent
#so the command fails


#this is very simple but deletes also 
find /path/to/myfolder/ -type d -delete

then I read this article and I tested this:

rsync -av --delete --remove-source-files /tmp/empty/ /path/to/myfolder/

where /tmp/empty/ is an empty folder, and it works like magic. Reading around it says that this is due to the fact that rsync has a LIFO way of reading file system info, rather than FIFO.