Poor bastards. 2-5 euro coins (1 or 2 euro) work perfectly. If you just put 'em on the button, it'll stay up, but when you press it, it stays down. Then, once you want normal motion again, you can just pull the button up and leave the coins on it. Does fine. The bad thing is, a pile of coins ain't very stable but there's always duct tape.
Besides, that's the only thing those coins are good for. Especially if you live in Russia, come on, a coin worth 1 kopeek? 0,34 euro cents that is, not too much in my opinion.