Not in Ireland - but we've one in Yorkshire where they're annually white-washed. In traditional societies, this was done to 're-clothe' the spirit of the ancestor in the stone. Similarities to this mythic theme occur where cloth is wrapped round certain monoliths (one on South Uist springs to mind, but I can't remember it's name - though it's on TMA somewhere!), dressing the spirit who inhabits the said monolith.