I don't know man, I'd toss the herbal to be honest. You're inhaling that stuff. In my mind it's not the fear that you're heating the aluminum to a certain temp, it's that the aluminum is physically migrating to your lungs regardless of whether it's being smoked or vaporized. Maybe if you crammed your VG innards just -full- of cotton or something like that so that it had no possible way to make it to your mouth... But just toss it.
If a little aluminum-y herb is the worst thing that happened to you today, then it's a good day.
The 2 piece grinder on puffitup.com is high quality, grinds fine enough for the MFLB, can handle 2+ g's at a time and is like 8 with shipping if you use the forum discount:
http://www.puffitup.com/product-p/puffitup2partgrinder.htm I'd recommend it. I also use a great, cheesy, cheap Chinese electric grinder which has served me magnificently for over a year now - I use basically no other grinder, and no other grinder can get it as fine. It delivers a coffee-grinder like grind without having an oversized cup you have to scrap and scrap to reclaim.
Edit: ah, here we go. This site has it overpriced by 10-15 bucks, but hunt around. I LOVE this grinder.
http://www.herbalsmokeshack.com/images/grinder-electric-herb.jpg
The motor still runs like a champ - the plastic cup however has started to feel somewhat brittle and I fear it may split in twain one of these days. But yeah, I love how it takes a menial task and turns it into a fun one, and how the thing never seizes up from all the gunk and resin like conventional grinders do. It'd also be great for people with weak or compromised hands, something I'll seriously have to deal with in time given my family history. If this grinder were to die, I would almost certainly get another identical one.