Bleaching experiments on Chinese pottery fine grains were conducted under sunlight and laboratory light conditions. It is found that the thermoluminescence (TL) at high temperatures can be bleached significantly, but no effects were observed on TL signals used for the pre-dose dating technique. It is concluded that the pre-dose dating technique can be applied to samples even after light exposures. Pottery samples of Tang Dynasty and New Stone Age were studied. Modifications to routine pre-dose dating technique are proposed with adding preheat procedures and using saturation exponential fitting for the sensitivity change data. The modified technique can extend the dating range to New Stone Age.