Hi Zara,
I'd recommend using peppermint oil capsules internally, if you can find them in US.
Holland and Barrett - Product details for Oil of Peppermint
Morgs hate peppermint and menthol. Yes on citronella essential oil externally. In the bath I find it drives them out, about 30 mins after getting dry. Great to add to coconut moisturiser on skin...again drives them out.
Exercise to the point of getting hot and shake off outside.
Using salt in bath or on skin in shower will also draw them out.
More stuff on me website here:
Morgellons UK - Awareness Campaign 2010 - Morgellons Disease - Support: Skin Cleansing
cheers
Jo