Unless this can is very old, I suspect that it has separated, floating the light weight components upwards due to heat and vibration (possibly in the delivery truck to the retailer). This leaves a thick crust on the surface and a resinous liquid right in the bottom of the can. I suggest you push a metal stirrer right to the bottom of the can where you will probably see the resin layer flowing into your disturbance.

If so, you can stir it back together and it will return to normal consistency. If not, Please email me the batch number on the can lid on the small white sticker and I will have the retained sample we keep from every batch examined. There are no solvents in Builder’s Bog, so the only thing able to thin it is polyester resin.

However, in all the 35 years since I first formulated it I have never seen a can less that 4 years old that was too thick. And normal shelf life at 25 deg C storage is 5 years minimum.

Regards,
Stuart Jordan
Managing Director
(26.3.2020)