Stan, you
can securely wipe an SSD. Sorry I go on a bit below, but please read, if you are interested.
You need to issue a ATA Secure Erase command to the SSD, which will wipe it completely and incidentally it returns it to a factory fresh condition and restores the performance to the level of a brand new SSD. (Even with Trim enabled, the performance of SSD's does slowly decline as they are used more and more and fill up more.)
To be clear, this does NOT just fill all the cells with zeros (with the inherent risk of data being hidden in spare blocks somewhere that you cannot get at). When you invoke a ATA Secure Erase command, the SSD controller applies a voltage spike to all of the cells simultaneously, flushing the stored electrons from the flash memory cells. It takes only a minute or two and it's done.
Issuing a ATA Secure Erase command on a Mac is easier said than done however! You need to boot a Linux image with the appropriate tools installed, and do it from there. Luckily there is such an image, that will boot your Mac and it can be found here:
http://partedmagic.com
It used to be free, but sadly they have started charging $5 for it now, but still not bad.
What you need to do is described here:
http://www.overclock.net/t/1227597/how-to-secure-erase-your-solid-state-drive-ssd-with-parted-magic
I have tested this, and confirm that it is easy and straightforward to do and it works. (When I did it first, the hardest thing was getting a linux USB stick to boot on an iMac, but they seem to have cracked that so it's now a doddle.)
Your SSD will be COMPLETELY blank and returned to factory-fresh condition. There are no recovery tools known to man that can retrieve any data from it once this is done. (OK, so maybe the CIA could conceivably get some scraps off it, but even then I think not. Unlike a hard disk where residual magnetic traces may be present, the SSD is completely wiped and you could hand it over to anyone you like with no fear of them reading anything.)
Hope this helps?