You can't
There is no way to erase your own history - or that of any other user - on WikiAnswers.
WikiAnswers ranks your contributions by how many questions, answers, edits and community work you contribute to the WikiAnswers community.
Actually you can't. Even I tried it.
WikiAnswers does not pay for contributions. All contributors and supervisors are volunteers who love the site concept.
Answer questions.
Its not
Unfortunately there is no way transfer contributions made as an unregistered user to a registered WikiAnswers account.
The WikiAnswers team can take an indefinite amount of time to erase useless or incomplete answers. Questions on WikiAnswers are answered by users of the website, not necessarily staff members. If you see a useless answer, remove it or flag it so that other users can see that the answer needs to be improved.
There is no end to the amount of contributions you can make.
Minutes
200,000 contributions
Rudiful2 is the top most answerer of Wikianswers based on the number of contributions.