import re
text = 'Must-have skills: -.Net programming experience; -2 years experience in C++.'
text = re.sub(r'[!,.:;—](?= |$)', ' ', text)
print(re.sub(r'(?i)(?:(?!\.net\b|\b-\b)[^\w\s])+(?=[^\w\s]*\b)', '', text))
aW1wb3J0IHJlCnRleHQgPSAnTXVzdC1oYXZlIHNraWxsczogLS5OZXQgcHJvZ3JhbW1pbmcgZXhwZXJpZW5jZTsgLTIgeWVhcnMgZXhwZXJpZW5jZSBpbiBDKysuJwp0ZXh0ID0gcmUuc3ViKHInWyEsLjo74oCUXSg/PSB8JCknLCAnICcsIHRleHQpCnByaW50KHJlLnN1YihyJyg/aSkoPzooPyFcLm5ldFxifFxiLVxiKVteXHdcc10pKyg/PVteXHdcc10qXGIpJywgJycsIHRleHQpKQ==