How to hand off your Mac for repair without worrying about insecure data on an SSD | Macworld

Don Kerns asks, in light of the removal of Secure Empty Trash for SSDs in El Capitan, about a repair operation he needs for his brand spanking new Mac:

My concern is providing the laptop to the service center with admin password or temp admin privileges as this appears to give them full access to my FileVault encrypted drive. It appears the only feasible way (other than securely wiping entire drive) to prevent admin access/copying my data is to delete certain software (Dropbox, LastPass, etc) and then secure erase the associated data folders. Is there a way to provide the service center with access to the MacBook Pro but not my confidential data stored on the laptop?

Unfortunately, there’s not....
http://www.macworld.com/article/3076157/macs/how-to-hand-off-your-mac-for-repair-without-worrying-about-insecure-data-on-an-ssd.html#jump