I was given a Meteor Siegen processor, it looked fine from the outside however when I opened the cover, it looks like they left the chemicals in each tanks to dry, thick dried dev and blix emanates strong smell...is this harmful to manipulate, which precaution shall I take?
In the case of developer, most any acid will remove it gradually over a period of time. The stronger the acid the quicker it removes it. OTOH, acid will make the blix residue worse so don't put acid or bleach into the blix tank. Those are bad combinations. Alkaline EDTA often will clean up the blix, but sometimes a scrub brush is needed.
There have been a couple of threads about this problem - check out the one below it might help.
I have used Lysol Toilet Bowl Cleaner - you might want to test it on an area to see if it will lift the residue. Be sure to use it in a well ventilated area because Lysol contains hydrochloric acid. When I used Lysol to clean old RA4 developer from a Durst processor it did a great job of dissolving the tar residue. After rinsing the tank I used the built in pump to recirculate the water through the system and started to find small black bits of tar in the pump lines. If I was to do it again I would either disconnect the lines or replace them so it would reduce chances of damaging prints.
There is commercial products available like Photofinish Soft from Photographic Solutions.
Mr Clean Magic Erasers also work well in cleaning the tanks but be careful not to use them in conjunction with chlorine bleach.
(there was a url link here which no longer exists)