Hi folks,
Got myself a new milling vice, a Vertex K5, and the thing is baked in solidified shipping grease which doesn't dissolve with WD40 or brake cleaner.
Got most of it removed but I can't get to the underside of the moveable jaw in order to clean it up.

There is a locking collar in front of the handle which takes the thrust when you wind the vice out. It's a standard steel collar with two grub screws securing it, which the manual describes as 'tapered pins' (I presume they are just grub screws with a point on the end, which fits into a dimple).
The problem is they take a 2.5mm hex key and they won't budge. Tried oil, heat, various types of hex keys, nothing. Luckily the heads on them haven't shredded but they definitely won't move.
Any tips on what to try here? Usually when I encounter this problem it's on a motorbike and I get the air gun out, but I'm worried about buggering the hexagon up.
Should I just drill em out?
Rich