  The algorithm of finding inverse multivector (MV) numerically and
symbolically is of paramount importance in the applied Clifford geometric
algebra (GA) $Cl_{p,q}$. The first general MV inversion algorithm was based on
matrix representation of MV. The complexity of calculations and size of the
answer in a symbolic form grow exponentially with the GA dimension $n=p+q$. The
breakthrough occurred when D. Lundholm and then P. Dadbeh found compact inverse
formulas up to dimension $n\le5$. The formulas were constructed in a form of
Clifford product of initial MV and its carefully chosen grade-negation
counterparts. In this report we show that the grade-negation self-product
method can be extended beyond $n=5$ threshold if, in addition, properly
constructed linear combinations of such MV products are used. In particular, we
present compact explicit MV inverse formulas for algebras of vector space
dimension $n=6$ and show that they embrace all lower dimensional cases as well.
For readers convenience, we have also given various MV formulas in a form of
grade negations when $n\le5$.
