Problem is, that's not really how it works. As i explained earlier, your capability to do that still reflects on you and in the character.
This is why different actors can't actually deliver identical performances even with the same character, plot, etc. While roleplaying doesn't always get to that high level of performance art, it is rooted in the same fundamental activity, and this effect actually becomes much more pronounced because we're talking improv rather than something prewritten.
Its not something you can avoid, because the harder you try to not be yourself the more your take on that character becomes unique to you, and that uniqueness is always rooted in your personality.