Roebelenii palm pruning
I have been pruning our pygmy date palms for a few years, but now the thickness of the trunk is getting to be much larger near the upper portion near the fronds. I have noticed that this mass close to the trunk is pretty loose. Is it OK to remove this loose material by merely scraping this material away, exposing the solid portion of the trunk? The trunk that is under this material appears to be healthy and looks nice.
I'm not exactly sure what you mean by the "mass close to the trunk." If you're referring to the uncut pieces of frond that were left behind when you pruned a frond, yes, you should go ahead and scrape or cut these down flush with the trunk. You would save yourself this work, and create a more lovely tree, if in the future when you prune a frond, you cut it flush with the trunk to begin with. Here is an article with some more information on Phoenix roebelini that might be of use to you: https://www.gardeningknowhow.com/houseplants/pygmy-palm/grow-pygmy-palm-trees.htm