“积灰”常见的英文表达是 “accumulate dust” （强调灰尘逐渐聚集的过程） 或 “be covered with dust” （侧重于描述表面被灰尘覆盖的状态）。
The old books on the shelf have accumulated dust over the years.（书架上的旧书多年来积了灰。）
The furniture in the abandoned room was covered with dust.（废弃房间里的家具积满了灰尘。 ）