I have a chance to buy some used 24# injectors for $10 but the seals/rings are old and appear to be dry rotted. It's been a long time since they've been used so I was curious if they make a rebuild kit with new seals? If they do what do they cost and should I do anything additional to make sure they are in good working condition before I install. I was going to go to the local hardware store and get rings that fit but then I thought I may have issues with heat or gas exposure?