[ophic]

Mostly smelly grey water on the inside, I would guess.

Simply stripping them and replacing the oil with something heavier will make a difference and is fairly easy and cheap to do, although takes a bit of time. I followed a guide by Delboy's Garage on youtube and I followed his suggestion of using bits of PVC pipe tools and they seem to work pretty well. I made it even cheaper by using a hosepipe clip rather than his hefty bracket.

Half the job is getting the bike securely supported with the front off the ground.

Replacements springs are easy to fit once you've got them apart but aren't that cheap unless you can source them 2nd hand. Linear or progressive is down to personal preference, except that if you want to fit emulators, you have to use linear. Stock are progressive, I think.