MOHALI: The age-old practice of shining the cricket ball has become a "grey area" and the game's governing body must provide clarity to end the prevailing confusion, England captain Alastair Cook said on Friday.

The method, ostensibly to generate more swing with the ball with one shiny side, has come under scrutiny after South Africa captain Faf du Plessis was declared guilty of ball-tampering by the International Cricket Council (ICC) earlier this week.

Television footage appeared to show du Plessis applying saliva to the ball while sucking on a sweet during the Hobart test against Australia but the Proteas captain has decided to appeal the ICC decision which cost him his entire match fees.

England paceman Chris Woakes rued lack of clarity on the issue on Thursday and his views were echoed by Cook ahead of their third test against India beginning on Saturday.

"I think Woakesey summed up quite nicely yesterday, it is a bit of a grey area at the moment," Cook told reporters at the Punjab Cricket Association (PCA) stadium.

"Players are slightly uncertain at the moment, what is acceptable and what is not acceptable. I haven't studied Faf's case that closely to see if he was taking the sweet straight to the ball or did he just happen to have a lolly in his mouth.

"I think the players are now, after the last 10 days, probably just looking to the ICC to clarify what is acceptable and what is not acceptable."

Cook was not sure how much it actually helped but preferred clearer guidelines.

"If they said you aren't allowed to directly put your finger from the sweet onto the ball, it might clear it up," he added.

His India counterpart Virat Kohli was accused by a section of British media of shining the ball with sugary saliva in the first test at Rajkot even though no charges were levelled against him.

"If I was doing something, ICC would have spoken to me," Kohli told reporters, calling such allegations a ploy to distract his team.

"I think it's just to take the focus away from the series, to be honest," said Kohli whose team have a 1-0 lead in the five-match series.

"It happened in Australia when South Africa won the series. I'm surprised the issue, what I've been told, came up in Rajkot but there was no mention of it until we saw the result in Vizag.

"I don't read newspapers. I was told five days after the thing came out and I just laughed it off. I don't pay attention to all those things.

"It's just that some people are trying to take the focus away from the series, good luck to them. We are totally focused on what we have to do in this game."