Here's what I do and it works for me. Firstly I use these:
earplugs on Amazon
I trim the long stem off because with a helmet they can be uncomfy. Just use scissors to trim 5mm or so off.
I ride a few times a week, all year. My lid is noisy. These earplugs are very cheap, but they work very well. I've used them for the past few years / 50k miles. Road use only but if I rode track I'm fairly certain they would be very good for that too. However, there are a few things worth mentioning that I don't think have been covered in the posts above.
Firstly, and most importantly, instead of moistening them with spit use olive oil. And don't scrimp on it either. When the earplugs are not actually in your lug 'oles, keep them in a
small 5ml plastic container. Half fill the container with olive oil, so when you get off the bike you can take the earplugs out and put them in the container. The earplugs will then be oily and can be put back in your ears easily when you're ready to ride off again.
This set up is very cheap, very effective and the properties of the olive oil guard against wax build up because olive oil effectively melts wax (put some on a candle - it softens it very quickly). Also, olive oil is really kind to skin.
The earplug, now effectively covered w/ olive oil from the container, means that when it's in your ear it shuts a LOT of sound out. Similar to putting your head underwater. The oil creates a kind of seal, keeping sound / noise out. Very effective.
If you've not used this kind of earplug before you MAY find that it pushes wax further into your ear, which can be a real nuisance because it affects hearing. This is not as problematic as you may think. Resist the urge to spend £80 or whatever by going for a syringing session at Specsavers or similar. There's no need. At least not until you've tried this: First, get some of these
100ml plastic dispensing bottles. Fill w/ olive oil and squirt some into your ear. By keeping some olive oil in your ear the build up of wax will quickly begin to soften. Of course, the oil will run out of your ear - so use your ear plug to keep it in. This may take a day or two. Sometimes even longer. I've slept this way, and by the next day all my hearing's returned. But it can take longer.
When you shower, take the earplug out of the affected ear, and work your little finger into your ear. Often, your hearing will return in full. Sometimes, when it doesn't, I personally use the plastic bottle to sluice my ear out using the warm water from the shower. GO EASY. Don't blast it into your ear like your squirting ketchup onto your burger at a bbq!! There's no need. The most important part of this whole process is the olive oil, and the way the olive oil softens earwax. If the build up is significant, the olive oil will take longer - but it WILL soften the wax and break it down completely. Judicious and VERY careful use of cotton buds is another way. Again, GO EASY. Let the olive oil (kept in your ear with an earplug for a day or two if necessary) work away on the wax, before using cotton buds. Be careful with the sluicing and the cotton buds. Less is more, etc. The only thing you CAN be liberal with in all this is the olive oil. Be tentative and softly-softly with everything else.
terrible father I know 
