I'm sorry, but there seems to be a confusion with your expression. Please make sure to use proper brackets and operators. It's hard to tell the actual equation as is. However, under the assumption that your expression is intended as (6m - 2n)^4 * (2m - 5n^3), here's how it would be simplified:
Unfortunately, the expression can't be simplified any further. The multiplication and the power operation cannot be distributed so the original expression, (6m - 2n)^4 * (2m - 5n^3), is already in its simplest form.