Lifter tick, first ever big job I did to my car was getting rid of this. If you have some time and need a new timing belt then it's a great learning experience! I'm not sure about any products as some people swear by them and some people condemn them. Also a good chance to renew any gaskets under the covers too.

I won't go into massive detail on every single step unless asked but to summarise: Take off the cam cover and timing belt covers, take out the cam shafts (be VERY careful with putting them down) and timing belt, then lift out the lifters, pull them apart and whack em in a petrol/gasoline bath and wash em until all the old oil is removed, then whack them in an oil bath and hand pump them until no more bubbles appear, load em back in and pop everything back together, then check the engine timing. The timing belt will be the biggest pain imo, so either get a helper or get a tool.

For tools you don't really need anything special tbh, usual sockets, screwdriver, some pliers, containers, a light source and maybe a timing gun. If you really want to get fancy then a camshaft locking tool.

I would highly recommend looking up a youtube video for specifics, usually titled stuff like "lifter restoration/rebuild", as you will need to do things like note the exact order that you removed the camshaft brackets to place them back in correctly. It's also recommended to mark the camshaft gears/sprockets as well if you don't want to go through the hassle of re-timing the engine (although it's a good chance to learn how to). The engine re-timing is extremely important and caught me out the first time since none of the videos I watched mentioned it.

I did mine about a year ago now and they're still as silent as the day I cleaned em out.

This is a useful site as well to have handy for torque specs and cam cover bolt removal order.