I have a Edlebrock intake that has some rust and light corrosion on the water passage. What is a good chemical to use to clean it? CLR cleaner?

 

Aluminum doesn't rust, so it's probably just some discoloration or residue.
Read the label on the CLR to see if it is compatible with aluminum - some chemicals will readily attack aluminum.
I used a wire brush to clean the whitish corrosion off the water ports on my intake.

 

If it's off the car, mag wheel cleaner works well. Also if you know someone with a bead blaster.

 

Don't bead or otherwise blast cast aluminum unless you plan on painting it. Once you open up the poors its a bear to clean. So a very high quality clear coat will be needed to seal it back up. Or powder coat or paint same as rest of engine.

 

I've bead blasted aluminum intakes and transmissions, then painted them with Dupli-Color DE-1615 aluminum engine paint.
It is very durable and looks like original aluminum. Also, has the high temperature benefit.
I've also used the Dupli-Color clear engine paint with good results except it yellows over time.
I was very pleased with the DE-1615 result.

 

Year One has a clear coat that doesn't yellow over time and seems to not be effected by gasoline. Its very hard/durable also.

 

Por-20 is the color of new cast aluminium it's very easy to clean and doesn't discolor with heat or gas. It's held up great on my manifold and water pump. It did bubble I bit on my headers though. I think I didn't prep them well enough.

 

https://www.yearone.com/SearchResult.../clear%20paint

Which one, oh, which one to choose?

I am guessing the ceramic type is best, $21 a can:

Part Number:1807-14148Z * Discount Exempt
Eastwoods 2K Aero Spray Ceramic High Gloss Clear Coat. 12oz can.
This aerosol paint allows you to paint with the precision and durability of a two component coating without a paint gun. Formulated with Eastwoods proprietary nano ceramic innovative valve and nozzle technology, combined with the two internal chambers ensure the right ratio is mixed every time. Sprays like a gun with a broader spray pattern than regular aerosols.