Mr Clegg said the Lib Dems had a track record of campaigning for change
Liberal Democrat leader Nick Clegg has urged voters to back his party as the best way to "rebuild" the economy and British politics.
He conceded that the expenses furore, rather than European and local issues, was "uppermost" in voters' minds.
But he told the BBC a protest vote for a minor party would not bring change.
Meanwhile Vince Cable says he is not "going off to join a Labour government" and would turn down the chancellor's job if it was offered by Gordon Brown.
As he travelled around ahead of the vote on Thursday, Mr Clegg told the BBC the expenses issue had been repeatedly raised with him on the doorstep.
"I think people will be asking themselves two fundamental questions, who is going to rebuild the British economy and who is going to rebuild British politics?"
The European and local elections should be used as "an opportunity to make sure that ... we are going to do things differently".
He said it was "totally understandable" that people might want to "lash out" with a protest vote but added: "The question is, what will that change?"
Cable: "Ten years ago, that kind of thing could have been possible."
"If we do things right, maybe something good can come out of all this mess."
He added: "We need MEPs who stand tall in Europe, don't just whinge from the sidelines but get the best out of Europe for your local area."
Mr Clegg also dismissed speculation Mr Cable might be in the running to replace Chancellor Alistair Darling should he be axed in the upcoming reshuffle.
Mr Clegg said his party would not help prop up a government which was "running out of road".
"Vince has made his owns views entirely clear," Mr Clegg said, "which is that he is part of the Liberal Democrat team."
"I am delighted that Vince and I work together as, I think, a highly effective team."
Earlier Mr Cable said some sort of Labour-Lib Dem alliance may have been "possible" a decade ago but it was not an option now.
His name has cropped up as one of the more unlikely potential replacements for the chancellor, following praise from across the political spectrum for his response to the banking crisis and recession.
But Mr Cable, a former economist who was a member of the Labour Party in the 1970s, told BBC Two's Daily Politics: "I am part of a Lib Dem team, I am not going off to join a Labour government."
He said a Labour/Lib Dem pact had been discussed between former leader Paddy Ashdown and then prime minister Tony Blair prior to the 1997 election but it was not an option now because confidence in the political system has "collapsed".
The Lib Dems' standing in the opinion polls, ahead of Thursday's elections for the European Parliament and 34 English councils, has varied wildly.
A recent ICM poll for the Sunday Telegraph put the Lib Dems ahead of Labour in second place, on 25%.
But a separate poll by Populus for The Times, put the Lib Dems on 15% and suggested it could come fourth in the European elections behind UKIP.
The chancellor is under pressure after having to apologise for claiming a service charge on a flat he was no longer living in after moving to his grace-and-favour property in Downing Street.
There has been widespread speculation that Mr Brown's longtime right-hand man in the treasury, Ed Balls, is poised to succeed Mr Darling who the Lib Dems say should be sacked.
A cabinet reshuffle could happen as early on Friday.
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