I have a '07 NC, nice condition and I want to keep it that way, so doing some rust proofing at the moment.
I’ve seen all sorts of information on removing the sill covers but it seems to conflict. So has anyone actually removed them and can tell me how to do it?
Look at MickAP’s post HERE .and THIS on Miata.net. It’s a fiddly job and you WILL break some of the small clips and possibly the large ones so stock up first. Having a 2nd person will help as you have to hold the sill in place so all the clips locate when you slide it to reattach.
Arm yourself with plenty of those small poppers, as I say in that thread the door card ones fit, same type size etc. The lower fitting clips (5 per side) stayed intact , just take care when sliding the sill off. I lay some offcut of carpet on the ground to catch it should I drop it to protect the paint finish.
Thanks for the advice, I now have both sill covers off, that’s the good news.
The bad news is that I just called the local Mazda dealer to order the clips and they have come up with an eye watering cost of £160 just to replace the 10 clips on each side! I had to check I hadn’t accidentally called a Bentley dealer as the cost is just way beyond anything reasonable!
Does anyone know another source for the clips, I don’t need the ones along the bottom as they are intact!
10x Mazda MX5 & CX7 Sideskirt / Sill Moulding Trim Clips D10E51SJ3 | eBay
An internet search should find what you need at a sensible price.
Andygadget posted a link above to a thread containing these below, cheap as chips and they also secure the door cards. Good company too, deliver fairly quickly.
Should mention if you don’t want to wait for the postman Halfords should have them in stock. I got some from them around 2 years ago, a pretty standard size fits many makes. Take a sample one to compare.
And btw I think the dealer is quoting you the full monty there, all clips, I know getting them that route is pretty expensive.
Mine refused to co-operate when refitting so I used a few self-tapping screws.
Tis out of sight and worked 
The dealer was quoting me for a total of 10 clips for each side, not including the ones along the bottom or at each end of the sill, about £7 each plus vat.
The person answering the phone had no idea what I was asking for, kept asking what seal clips were, could hear them asking if they were available separately or came with the sill, still didn’t understand when I said side skirts. Eventually got someone who understood and he admitted the pricing was crazy.
I’ve ordered ones using the link provided together with a few other useful ones.
I bought my car from a bloke who lived on a farm.Sill covers were full of straw and grass. You have to be bold when taking them off and expect ot break some clips, I found this video useful.
MX5 NC Sill Panels & Plastic Welding - YouTube
Was being a bit of a noob wondering how to re fit them but did some plastic welding, put the clips in the metal sill then thump the covers on. Video also tells you where to buy the clips
That’s a good guide there.
An alternative which I had to hand to bond the plastic brackets back on was a polypropylene cement. Mine was a left over from a job, the type of cement/glue used to bond and seal plumbing joints, soil/rainwater pipes.
The proper clips were delivered next day and so cheap it didn’t seem worth trying to glue anything. Of course you can glue anything with PU adhesive at just a few quid for a big tube, but I like to keep things as they were designed.
I’ve just ordered a load of clips for my BMW e39 M5 which comes back from the paint shop at the end of the month following a full bare metal respray.
Having removed all the arch liners and sill covers I found zero rust on my '07 MX5, not bad from what I hear.