Sort of on topic and the extraordinary knowledge base on this forum will, I'm sure, solve a mystery for me!
I have two Oral B rechargeable toothbrushes – one for the downstairs and one for the upstairs bathroom. I use one in the morning after my shower and one upstairs at night before bed. Useage is essentially similar, similar toothpaste, similar cleaning time, both carefully dried after use and replaced in charger. After a couple of days use, the upstairs on its base starts to collect a hardening blob of toofh paste between the brush handle and the base, the downstairs one remains consistently clean. I have just cleaned the upstairs unit for the third time in a year and it's driving me crackers!! Why the difference and, given that both are cleaned and dried after use, where is the toothpaste residue coming from????? Other than overtime by the workshop gremlin, I have no idea!!
rgds
Bill