Hope I'm not too late to answer, but when asked to do this, I crossover/blacklist all the number.

The only valid reason they would need to see payslip is to verify employment, not looking at salary. Why the heck anyone would share their current salary is beyond me. You lose the bargaining power.

Granted I've worked for only less than 10years. But I've jump to few companies and the amount of increment that I got for every move was rather decent. I think it's mostly due to my firm stand on salary negotiation.

If any HR people read this, and you still ask for candidates current salary "to proceed further", your hiring policy sucks.

I will just say no.
But maybe the more proper terms sounds like so. "Unfortunately my current remuneration is confidential and I'm bound to not share it as per my employment contract".

But do digest this http://www.kalzumeus.com/2012/01/23/salary-negotiation

We have to negotiate from position of 'yes if'. Meaning make sure you're positive that you're in, minus the salary part. Also stay firm, make sure you're ready to walk away if they unable to meet the expected number.