I need 2 formulas

1. a formula to do the following:
in A1 is 00003056-021
I need B1 like this - if there are leading zeros then remove first 4 zeros
(only 4 and not 5). I need B1 to have 3056021 without the dash.

2. a formula to do the following:
in A1 is 30701267-042
I need B1 like this - if there are no leading zeros then remove digits
5-6-7-8 and the dash. I need b1 to have 3070042.

Now, how do we combine both formulas?

Thank you.