Put a message in a bottle and throw it out to sea

I’m scared/worried/concerned – more than anything – that it’ll end up washed up on the same shore…or a nearby one. I live on the coast so it could easily skip a few beaches and then become washed ashore again x__X Oh well. Also, is a plastic or glass bottle better? And I really don’t know what to put in it…Hmmm…

There’s a few problems I can see:
1. If you use a glass bottle it will probably smash before it gets anywhere
2. If you use a plastic bottle it isn’t environmentally friendly
3. You’d have to throw it off a dock or something so that the message doesn’t wash back up onto the same beach you chucked it off…And even then, it might.
4. I have no idea what to write on the letter.
Anyone got answers, suggestions or ideas?
I’ve seen the oceangram.com website but it just isn’t the same. I’m not expecting this to be some big romantic thing, I just think it’d be a nice present for whomever finds it.