Don’t ever write any really private data to the SSD in cleartext. Use an encrypted file system. “Erase” by throwing away the key. That said, for modern fast SSD’s the performance overhead of the encryption might be a problem. For the old SATA SSD in my laptop, I don’t notice it.

“Why are we running from the police, Daddy?”

“Because we use Emacs, son. They use vim.”

–old Slashdot T-shirt