I prefer not to handle mine if they are clearly in blue. First, it is a time when many cannot see very well, so in that case it is a good way to get bitten. Second, many snakes seem to feel slightly "ill" during this period... I imagine it is a lot of work for their systems, and I prefer not to tax them during this time period.
If you absolutely must handle during a shed or in-blue period, do so as gently as possible, and as quickly as possible.