User blog comment:Genthar/About Cyro Grenades and Holy Hand Grenade/@comment-5276866-20121026205948

Even thought this blog (and the Wiki pretty much) is dead, I'll post for anyone that comes here, like for future refence:

SAS 2/Insane Asylum:

Holy Hand Grenades will appear randomly, follow the yellow blips that pop-up on your radar scanner. They go off as soon as you touch them (can't be stored for later sadyl), so make sure there is a crowd to take out, it will take out almost all Zombies on-screen, but don't wait too-long, they will disapear.

SAS 3:

You start with 6 Cyro's, and more can be found in the crates (see picture if anyone doesn't know what I mean) that appear randomly. I just recently started the version with Holy Grenades, and I haven't gotten any yet. I didn't see any in the Premium section, so I think they are probably found in those crates, but are just rare.