If you are preparing it from pill form, this is next to impossible..I mean, there ARE quite a few members on the site here that have done it, like neurotic said, you'd be fuckin with a PEG/ethanol mix which is a huge hassle (not to mention it's not something I'd wanna fuck with and shoot up my arm..and I've tried the infamous "krokadil"). That being said, my friend, just eat/take them sublingual, it's the best way to achieve maximum results IMO, unless, as he also said, you have a couple ampoules and need to sedate yourself stat..lol, and I've been on almost every prescribed benzo you can imagine in Canada (even got my hands on a 120count stash of bromazepam, which, from what I've read, isn't even available in Canada, which brings me to wonder how the hell the person I nicked them off of got them in the first place..) but I'm getting off topic. My apologies; I just dosed an extra 50mg on my methadone and chewed up 4 valiums..I'm gettin bubbly
I hope this was at least slightly helpful; just from my ten(ish) yrs of experience, chewing/swallowing valium is most effective, their size/makeup makes sublingual a little tough IMO.