Today I got asked how to send cold leads/emails in bulk to a bought mailing list.....this topic is going to throw up some controversy but if you can't break something to risk some things it's not worth it in my opinion.
What do you do if you've got a mailing list of 50k? I had this problem earlier this month that I luckily managed to solve. I bought a 50k mailing list to test and run some experiments on. First of all, it was a relevant list of people interested in technology and gadgets, not a hair and beauty list which would be pointless to buy if you're selling technology.
If you try and send 50k emails first through anywhere you'll get blacklisted. You could try asking someone else to do it for you on places like Up work but they could steal the data and spam it themselves till it becomes useless.
If you have a number of emails that no longer exist and the place you're using to send them gets a whiff you'll get blacklisted.
You need to use a tool called emaillistverify (google it) this will run all the emails you have and check that they are real + don't have any spam-traps.
After doing this you should see you won't get as many people unsubscribing or you get black listed.