Dutch, PM me. I can help you along - I wont be cleaning many of these myself sadly.
My first step these days is to seperate out any for preferential treatment and then put the coins into deionized water (couldnt get distilled) to get the loose dirt off. After that, change the water and leave for a week or so. Then its into the oil with the survivors. I do love the subtle fizz they give off when you first drop em' in.