Hi, I am at my wits end with ds1 (6) and (only) taking things away isn't working anymore so I want to start the marbles in a jar method where you add marbles if they're good and take them away if they're naughty. Can someone who already does this explain to me how many marbles at the end of the week gets the child a reward/ how many is not good (and what happens then?); how big is your jar, how many marbles do you give out in a day on average, etc. please? TIA.