Hi, in a recent episode of G/W Monty Don showed how to sharpen your garden tools including a secateurs,it might still be available on iplayer,(use an oilstone with some light machine oil and rub the curved blade in a figer of eight over the lubed stone,
I take mine to our Blacksmiths to sharpen. Hubbie had a go with the oilstone but didn't sharpen them correctly . Blacksmith said it can be a tricky business if you don 't know what you're doing.
sharpen if in good conditon ,bin if not.
I did a workshop at Jekkah's herb farm a couple of years ago and one of the first things she asked the group was "how many of you clean and sharpen your secateurs after every use?" I wasn't the only one sheepishly admitting we rarely did it. In fact I soon bought a sharpening iron form my local garden centre (one of a chain, so not necessarily specialist) and sharpened all my tools for the fist time ever in many years of gardening. It's totally transformed my life!
Lots of online suppliers if you cna't find anything locally.
If you're an 'abuser' your blades will end up with nicks in them in which case you'd need to have them put on a grinder (by someone who knows what they're doing) - or bin them. Shoe repairers often sharpen blades, btw. Finances and guilt about landfill have motivated me to be more careful in using the right tool for the job and I learned from the pros on the telly and in books how to sharpen them. I don't sharpen them every day but I do clean them every day that I use them. .
I've become rather emotionally attached to my little family of secateurs now that I've had them a few years and would be a wee bit upset if I (or anyone else) damaged them beyond repair.
Try folding a sheet of used foil over a few times then cutting the folded foil into strips. It works for sharpening scissors.