Had a reason to refurbish the compass in the Auster Autocrat,ie inverted type, due to the great diffuculty in trying to read the direction indicator. The fluid had turned yellowish and the white markings had faded. Checked with several 'experts' and was advised to use metholated spirits- white spirit- ethonal- mineral turpintine- and several others. Was warned if the compass card is made of mother-of-pearl shell white spirit would warp the card. Used mineral turps in the compass and sealed up with silicon base sealent (black). Hardest part was getting the turps in upsidedown
