It could really use some post-processing love, the moire is very visible here. It's hard to give hard and fast rules about moire avoidance, but you should experiment with your scanner's settings (DPI, orientation) and consider applying selective Gaussian blur on the image.

Avoid moire: Don't scan at a higher resolution than the DPI of the image.

There are filters specifically designed to eliminate the moire pattern while keeping mode details than a blur or a scale would.

Ah okies, apologies for that. I'll have a mess around with my scanner and see what I can do to fix up any images that need it.
Again I'm sorry about that ^^;;

I'm of the opinion that filters are bullshit.

Unless you scan it three or four or 12 times and use some batshit-crazy interferometric filter that nets you 12000+dpi or some shit, you're not really going to get rid of it properly. AND THEN the best you're going to do is sharply define each one of the ink dots. And then guess what? You're going to drop it back down to 300-600 dpi anyway because that's what you print at because you don't own a print shop.