Be careful in investing on different bitcoin mining sites. There are lots of mining sites before that later turned into SCAM. I was a victim of a popular mining site before. The site lasted for almost 6 years (correct me if I'm wrong) and one day, we cannot visit the site because according to the staffs, it was hacked. Many investors lost their investments on that site.
This isn't about mining sites, it's about mixing sites.
If you put your Bitcoins into a mixing service you can't be sure the coins you get won't be tainted, but it's safer than keeping coins if they're dirty coins. You're safe in the sense that they won't steal your coins as long as they're already trusted services like BitMixer.io or something.