It obviously depends very much on what kind of trim pieces you are wanting to respray. What they are made of and the sort of finish you are after.
I am not sure what the trim is you wish to renovate but most cars of the last. 25-30 years or more have utilised some form of moulded hard plastic or softer rubberised style materials.
Hard plastics are straight forward enough to paint even with cheap generic spray paint.I live in the UK so have almost exclusively used touch up spray paint in cans from Halfords (if you're from the UK then you know what chain I'm referring too but I'm afraid I don't know what the US equivalent would be) but there are similar products from Carplan and Holts, if they still exist.
All the same you will know the kind of paint I mean. The one you have to 'shake vigorously' for 2 minutes to mix the paint evenly They always have a marble in the can so you can hear it as you shake...... hence the familiar term 'rattle cans'.
Yes, they are cheap, nasty, smell bad or can make you high though not in a nice way and are universally used by graffiti artists to colourise our city centres but despite the general notion they're only usrful for a patch up job you can get an amazing finish using these products.
It's often been said that it's 90% preparation when it comes to all manner of DIY tasks and it had never been truer than with getting the best finish with spray tins.
The use of a good thorough coating, several layers preferably of plastic primer are essential. The secret is thin coats and lots of them built up slowly, dusting coats that dry quickly with 10 mins between each one.
After building up a good coating let it dry overnight then the next day give it a mild rub with 600-800 grit wet&dry sand paper.
Pour some warm water in a bowl and a couple of squirts of detergent/washing up liquid then rip up the sand paper in strips and let it soak for 10 mins or so before using it.
Afterwards thoroughly wash and dry the trim piece th then a little later apply another coat of primer.
Next day, sand, wash and dry it again and apply the colour coat taking the same approach as before. Build it up slowly and methodically then sand lightly once completely dry.
Then finally lacquer the trim piece following the same approach. I believe you know lacquer as clear coat in the US.
Also the entire process from beginning to end needs to be done in a clean, dry, warm environment where little or no dust can be kicked up into the air.
The more time and care taken in each step will result in a far better outcome. I've colour coded many body parts this way and it truly is possible to get a finish as good as the OE paintjob.
As for chromed/chrome effect trim pieces...... window surrounds for example I'm not sure it's possible to replicate the original pieces with aftermarket spray tins, they never seem to live up to their promise in my experience.
Far better to try ebay or a local scrapyard for pars from another vehicle.
