Stephen,
I had a wry smile on my face when I read your posting
I have only had that problem whenever I took on a new guy, and they would go through no end of scrims in a day.
Generally I have never had a problem with scrims over sudsing in the washing machine, I wait till I have a full load for the machine, put a small amount of powder or whatever in the machine, and wash on a medium heat setting and on 'quick wash'.
Have experimented in the past with fabric softeners, but personally I prefer them un-softened.
But you don't need to put them on a boil wash whatever method you use..........well, unless you buy them unbleached, then I have always found a full boil wash for the first clean a necessity.
Ian