I cut off the rear fan grill on the back of my my Sonata using some tin snips. Made absolutely no difference to temperatures so I can't remember it.

Unfortunately, I'm now left with jagged / sharp edges. Is there any way to remove these easily?

(I tried filing them down but it didn't work and using a hacksaw doesn't work because the hole is too small / circular).

1) Grinding attachment on a Dremel tool,

and/or

2) Rubber "C" channel molding to cover the edges.

Just a note on my experience, I don't think temps changed much for me either but noise was noticeably reduced.

Files will work. Get a half-round file with a medium or heavy grain and file those jagged edges away.

When I do it, I don't wear no stickin glove. I get my hand in there with those sharp edges and work that file back and forth. the blood from cuts in my hand and the sweat from workin that file back and forth mixes together and lubes the file. Thats the way I do it and thats the way I like it.

Seriously, I'm with Michael Dooley on this one (I dont own a dremel). It works for me. Just need patience, a glove and a good file (see Mikes recommend)

The rubber mould is the easiest (laziest) option . I gave up on grinding it down, and spent rather a few pennies on such a low-cost yet very handy item .

I would imagine just putting moulding around the edges also has the advantage of a 0% change of small metal filings frying some expensive electronics.

Well - that, and it take a heck of a lot of effort