re = /^\+?0*3*0*|[^\s\d]/m
str = '+331234567
+3301234567
00331234567
003301234567
0331234567
033-123-456-7
0033.1234567'
subst = ''
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html