The function scalarpart is most effective on products.  It will try to simplify other expressions to products.

This function collects scalars and constants from a product, removing those parts which are forms or are undeclared.

This function and formpart may be used together to separate a product into scalar and form parts.

The command with(difforms,scalarpart) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{difforms}\right)\:$$\mathrm{defform}\left(f=\mathrm{scalar}\,c=\mathrm{const}\right)$

$\mathrm{scalarpart}\left(2\left(vf\right)\&ˆ\left(cu\right)\right)$

$2fc$