I just found mites on my new redtail boa earlier this week and that was a first for me too. You said the bugs are greyish...are they closer to white or black? Small white bugs called springtails aren't harmful to snakes (or any other animals for that matter), but if they're dark (almost black) then they might be mites. I'd be surprised if they were springtails since you said you kept the snake on newspaper.
If they are mites, there are a bunch of ways you can get rid of them. Just do a search on here and you'll find dozens of "this worked for me" remedies. Here's mine:
**** BUT I wouldn't use this on your corn if I were you unless somebody else who is more experienced can back me up. I never read anything about it on this forum before, but a lot of boa people suggested I use it for my boa and it worked great. I don't know if it would affect a corn differently though. ****
Wal*Mart sells Repel 0.5% permethrin spray in the camping section. Take the snake and the water dish out of the viv, fog the viv down real well with everything else in it (decorations, hides, etc). Leave it all sit with no ventilation for an hour or so, then let it air out for 1.5-3 hours (a fan will help speed this step along). With the same substrate still in the viv, put the snake and water dish in. All of the eggs will die, and any mites that are on the snake will eventually come off, come in contact with the stuff that was sprayed, and will die. If you want to take it a step further, soak your snake to get the mites off (that's what they'll do on their own a lot of times if they have mites anyway).
Like I said, I did this with my boa, and by the next morning I couldn't find a live mite anywhere on the snake or in the viv. Just be careful not to treat the snake or the water.
Has anybody else used this method with corns???