The independence referendum should have tight spending limits to prevent it being "bought and sold for English gold", according to the Scottish First Minister.
Alex Salmond offered some "free advice" to the US on democracy and campaign spending limits during his visit to Chicago for the Ryder Cup golf tournament.
Speaking to local radio station WBEZ, he said there is still "a persuasion job" to be done to convince people in Scotland to vote for independence. He said "bigness" does not guarantee economic security, and predicted Scotland's fortunes as a small country could be boosted by an oil price surge as the world economy recovers.
Mr Salmond also revealed that he has donated a copy of a 15th century Act of the Scottish Parliament to a Chicago golf club, which restricted golf in favour of archery training to defend Scotland against the English.
WBEZ suggested that a deciding factor in the referendum may lie in "how snotty the British get about this". Mr Salmond replied: "I love the word snotty. I've heard many descriptions about what is going to decide the referendum but snottiness is not one (of them).
"We're two years out from this referendum and I think there is a persuasion job to be done, but I think we're capable of having that persuasion campaign. And I think given the circumstances we'll face, and the opportunities that we have, I'm confident that we'll get a Yes vote for independence."
Mr Salmond was due to return to Scotland on Monday to prepare for his forthcoming meeting with Prime Minister David Cameron to conclude their negotiations on the referendum process. The wording and number of questions is expected to be finalised, alongside the possible inclusion of 16 and 17-year-olds in the vote and campaign spending limits.
In the Chicago radio interview, Mr Salmond borrowed a phrase from Robert Burns to emphasise the need to ensure either side doesn't "buy the ballot". He said: "It's rather important to have limits on campaign spending and that applies to elections and referendums. Why? Because you don't want someone to buy the ballot.
"And certainly if you're coming to a vote on independence, you don't want it 'bought and sold for English gold'. We wouldn't want that to happen. A tight campaign limit, a fair campaign limit that is the same for both sides of course, is very important in a referendum.
"And if I could offer this free advice to the American people, I think given the democracy that is so evident everywhere in America and the wonderful free expression of opinions and ideas, if there was a way to do that without spending billions of dollars then I think a lot of people would like that as well."