How to remove a spring from your shock:
First, remove the lower hard wear out of the eyelet to allow the spring to pass through or over the outlet. Now take the pre-load collar and go counter clockwise. You can use a double barrel spanner if it is really tight for more leverage on the collar. Once it is loose, bring the collar all the way to the top, press the spring clip forward in the spring, which should give you some clearance to pull the clip out. Once the clip is removed, pull the spring off, change your spring, wipe away any grit and grime, and now reinstall.
When you reinstall, install the spring clip, make sure the open end of the spring clip is 180 degrees away from the open end of the spring coil. This will give it more support. Install, rotate, and everything will clip back into the eyelet. Now turn the collar to where it engages.