'Dust-free grit blasting' for concrete - how does this work?

[Pete.]

Got any photos and dimensions of the affected area? That might elicit more educated suggestions. At least it should discount some courses of action.

 

[mangocrazy]

I can get some photos taken easily enough. The size of the cellar is (from memory) 3.4m x 3.2m or about 11 sqm. It has a stone table occupying part of one wall and two brick piers supporting the chimney breast in the above living room on another wall.

It also has a fairly healthy population of spiders. But you probably didn't need to know about that...