One thing I've found that greatly helps is using EKG gel on the strap every ride. This will last you for years: http://www.amazon.com/Spectra-360-Electrode-Gel-Laboratories/dp/B0093J2GM4/ref=sr_1_2?ie=UTF8&qid=1374794485&sr=8-2&keywords=electro+gel

Some kind of app that filters out HRM readings over a threshold would be really helpful though.