The thermal pulsing technique gives information about the spatial distribution of charge and polarization through the thickness of electrets. This paper discusses methods by which this technique is applied in practice to the problem of determining these distributions. Several possible sources of systematic error in the experimental data are identified, and methods are discussed for eliminating these errors. A physical approach to data analysis is discussed which is complementary to a previously published mathematical analysis. Examples are given where this approach has yielded useful information about the charge or polarization distribution in insulators.