Relays green r6k5 & yellow r6k5

Hi, can anybody advise me on the following, i have a few yellow R6K5 that have slight browing on the top orlower side, Do i need to replace these even though they seem to work?. Also what is the Difference between the Green Relays and the Yellow relays?, as they have the same reference mark on the top. i.e R6K5. Any advice welcome.......

The colour difference can denote two different things;
a: different load factor e.g. 20A green, 30Ayellow.
b: you will see that some of the green relays have 5 pins as opposed to the yellows 4 pins. This is usually to operate something at two different power settings e.g. AC condenser fan etc..
Ampereages quoted are just examples and may not correspond to actual values as fitted to your vehicle!

Do not know if it's common but I have had similar browning on a couple of relays. On driving the vehicle for short periods, found these relays to be very hot to the touch. Replaced and all now cool. Used best quality Bosch aftermarket ones as cheaper than original Siemens from stealer.

Hope this helps.

yup, cheers will get some fresh ones..