How to remove all leading zeroes in a string

Question

If I have a string

00020300504
00000234892839
000239074

how can I get rid of the leading zeroes so that I will only have this

Answer 1

Regex was proposed already, but not correctly:

output is then:

4523423400023402340240

Background on Regex: the ^ signals beginning of string and the + sign signals more or none of the preceding sign. Therefore, the regex ^0+ matches all zeroes at the beginning of a string.