Need help wiping MacBook Pro for recycling

I have two old MacBook Pros (2009, Intel Core 2 Duo, running OS X) with FileVault. I need to wipe them before recycling, but I cannot get them to reboot in recovery mode (I tried Command + R and Command + Option + R). When I go to the device utilities and try to erase them, all options are greyed out other than Erase free space. One system has FileVault turned on and one was never turned on, so it doesn't seem like that is the issue. I have tried everything I can find here and elsewhere online.