According to me don't use black hat seo technique because now it will rank after that all your keywords will go back to 10 th page of the search engine
It is not a good practice to use Black Hat SEO techniques, because it is not allowed by Google. If anyone use those techniques, may be website will get rank soon, but it will be not for long time, as Google will ban such sites. Better to use white hat techniques, which will give long term result.