You can absolutely clean the rear element as you've discussed - it's done exactly the same as the front element is cleaned.

Caution must be used because if, for example, a piece of grit were on the rear element when you used your cloth, and you damaged the element's coating, the damage is far more likely to affect your image quality than it would be if you did the same damage on the front element. The rear element is very close to the film/sensor plane and the image is nearly in focus at this point, whereas the front element is far from the capture plane and far from the point of image focus, so a surprising amount of dirt or damage can be on a front element with minimal effects on image quality (except if you are shooting into strong light, like the sun, when the issues will tend to cause flare).

Blow off any particles or gently brush them off, using a blower brush, then use a microfibre cloth, or a piece of lens cleaning tissue moistened with lens cleaning solution, to clean the element. The standard advice is to clean from the centre out to the periphery/edge.