The short answer is that, no, it's not safe to invest in ICOs. At the same time, if you're smart, then a risky investment in the right ICO can give you life changing rewards in the future. A lot of what you should look for is a coin's long term staying power; if it's going to be around for a long time then the chances are good that you'll eventually reap the rewards you want. For it have good staying power, though, it has to offer something to the marketplace that's unique (or "unique enough") that a lot of people are going to want. You also need to familiarize yourself with who's behind the coin, otherwise you could end up scammed out of your money or even end up with it "refunded" (after the BTC you used to buy it drops a few thousand dollars per coin, as happened with TokenPay). On the flipside, had you been able to invest in certain ICOs (such as SpectreCoin), then you'd be enjoying some life changing profits right now. I'm sure there are some ICOs out there that you could profit from, if you HODL for awhile and pick your coins carefully.

I know it's not much, but that's the best I can tell you, man. It's risky, way too risky for me, I think, but man can it pay off if you choose wisely.