Hydrospares would like to express our gratitude for an excellent help article - written by our customer Mr Derek G Savage.
Background
The Airbath Original has 234 'air jet' holes in the bottom of the bath, arranged in 21 circular patterns of 11 holes each, plus one group of 3 holes near the drain plug.
From misuse - bath used for showering only over a very long period without afterwards applying cleaning tablets and liquid - the holes had become completely blocked with 'gunge'.
Repeated use of lots of 'super' de-gunging tablets and grease remover fluid failed to unblock ANY holes.
Described here, for Alice Jones at Hydrospares, Redruth, who was so very helpful in providing me with an understanding of the bath construction, is what I did to unblock the holes. The Airbath functions as new.
Tools needed
Pin chuck.
Twist drill 1.5 mm diameter. 
Vacuum cleaner with nozzle attachment.
Toytown diy-standard chuck is no use. A high quality chuck is needed to ensure a firm grip on the drill.
Procedure
1. Fit the twist drill into the pin chuck and tighten the chuck.
To ensure a good grip on the drill, the chuck may tightened on to the drill using a mole grip and plier.
2. Offer the twist drill to a blocked airjet hole and rotate the pin chuck/drill 'softly' clockwise with the fingers, allowing the drill to self guide into the hole and penetrate the gunge. Do NOT push the drill into the hole.
This 'pulls' the gunge from the hole by the drill flutes, so that the gunge is on the base of the bath and the hole is clear.
Remove the twist drill from the airjet hole by continuing to rotate the pinchuck/drill clockwise and gently pulling it out at the same time. The gunge may then be removed from the bath by vacuum cleaner - a cloth would smear the gunge back into the holes.
3. Repeat (2) for all the airjet holes that are blocked.
4. Clean the bath using degreasing fluid and tablet as sold by Hydrospares, and the recommended procedure for these products, then wipe bath dry.
CAUTIONS
Don't let the drill end of the pin chuck contact the bath surface, as this COULD cause surface damage to the bath. A piece of adhesive tape/cloth could be placed over the pin chuck end, although I did not find it necessary - just gentle operation.
Care should be taken not to enlarge the airjet holes. Hole AREA is proportional to the SQUARE of the diameter, and with so many holes the total area open to air flow would be so increased by even a small increase in the individual jet area that the air blower would not be able to create sufficiently strong airjets.
Derek G Savage 21 Feb 2016
