diff --git a/diigo-cache/src/api.ts b/diigo-cache/src/api.ts
index 745cd9b..f200ec3 100644
--- a/diigo-cache/src/api.ts
+++ b/diigo-cache/src/api.ts
@@ -28,9 +28,10 @@ type Fillable = {
 	startFill(opts?: { pagesPerStep?: number }): Promise<FillStatus>;
 	fillStatus(): Promise<FillStatus | undefined>;
 	stopFill(): Promise<FillStatus>;
+	invalidateRecent(days: number): Promise<{ pages: number }>;
 };
 
-/** a cache's fill job, and nothing else */
+/** a cache's fill job and page invalidation, and nothing else */
 export class FillCap extends RpcTarget {
 	#cache: Fillable;
 
@@ -55,6 +56,13 @@ export class FillCap extends RpcTarget {
 	async stopFill(): Promise<FillStatus> {
 		return this.#cache.stopFill();
 	}
+
+	/** drop the cached pages holding anything updated in the last `days`
+	 * days (1–3650), so they refetch */
+	async invalidateRecent(days: unknown): Promise<{ pages: number }> {
+		if (typeof days !== "number") throw new Error("days: expected a number");
+		return this.#cache.invalidateRecent(days);
+	}
 }
 
 /** what the holder of a private cache's key may do */
diff --git a/diigo-cache/src/cache-page.ts b/diigo-cache/src/cache-page.ts
index c019f62..b34d1ae 100644
--- a/diigo-cache/src/cache-page.ts
+++ b/diigo-cache/src/cache-page.ts
@@ -28,12 +28,18 @@ export const CACHE_PAGE_HTML = `<!doctype html>
 <p id="private-status">no fill job yet</p>
 <button type="button" data-target="private" data-action="start">fill</button>
 <button type="button" data-target="private" data-action="stop">stop</button>
+<p><label>invalidate the last <input type="number" id="private-days" min="1" max="3650" value="7" size="5"> days</label>
+<button type="button" data-target="private" data-action="invalidate">invalidate</button>
+<span id="private-invalidated"></span></p>
 </section>
 <section id="public" hidden>
 <h2>public cache</h2>
 <p id="public-status">no fill job yet</p>
 <button type="button" data-target="public" data-action="start">fill</button>
 <button type="button" data-target="public" data-action="stop">stop</button>
+<p><label>invalidate the last <input type="number" id="public-days" min="1" max="3650" value="7" size="5"> days</label>
+<button type="button" data-target="public" data-action="invalidate">invalidate</button>
+<span id="public-invalidated"></span></p>
 </section>
 <p><a href="/">← home</a></p>
 <script type="module">
@@ -105,6 +111,13 @@ async function main() {
 		button.addEventListener("click", () => {
 			const { target, action } = button.dataset;
 			const j = job(target);
+			if (action === "invalidate") {
+				const days = Number($(target + "-days").value);
+				j.invalidateRecent(days)
+					.then((r) => ($(target + "-invalidated").textContent = "dropped " + r.pages + " cached pages; fill to refetch"))
+					.catch(report);
+				return;
+			}
 			(action === "start" ? j.startFill() : j.stopFill())
 				.then(() => refresh(hasPublic))
 				.catch(report);
diff --git a/diigo-cache/src/cache.ts b/diigo-cache/src/cache.ts
index dccbcf0..6d3c277 100644
--- a/diigo-cache/src/cache.ts
+++ b/diigo-cache/src/cache.ts
@@ -245,6 +245,37 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 		return stopped;
 	}
 
+	/**
+	 * drop the cached pages holding anything diigo updated in the last
+	 * `days` days, and every page before them (newer still; and new
+	 * updates push items back), so the next read or fill refetches them.
+	 * Item rows stay. Returns how many pages were dropped.
+	 */
+	async invalidateRecent(days: number): Promise<{ pages: number }> {
+		if (!Number.isInteger(days) || days < 1 || days > 3650) throw new Error("days: expected a whole number from 1 to 3650");
+		this.#schema();
+		const cutoff = Math.floor(this.#clock.now() / 1000) - days * 24 * 60 * 60;
+		const sql = this.ctx.storage.sql;
+		const deepest = sql
+			.exec<{ last: number | null }>(
+				"select max(page_members.page_num) as last from page_members join items on items.item_id = page_members.item_id where cast(items.updated as integer) >= ?",
+				cutoff,
+			)
+			.toArray()[0]?.last;
+		if (!deepest) {
+			console.log({ event: "cache", kind: this.kind, outcome: "invalidated", days, pages: 0 });
+			return { pages: 0 };
+		}
+		let pages = 0;
+		this.ctx.storage.transactionSync(() => {
+			pages = Number(sql.exec<{ n: number }>("select count(*) as n from pages where page_num <= ?", deepest).toArray()[0].n);
+			sql.exec("delete from page_members where page_num <= ?", deepest);
+			sql.exec("delete from pages where page_num <= ?", deepest);
+		});
+		console.log({ event: "cache", kind: this.kind, outcome: "invalidated", days, pages });
+		return { pages };
+	}
+
 	/** one fill step: up to `fillStep` pages, progress saved after each,
 	 * then the next step is scheduled (or the job ends) */
 	async alarm(): Promise<void> {
diff --git a/diigo-cache/tests/caches.test.ts b/diigo-cache/tests/caches.test.ts
index 4df7c76..c8d93d4 100644
--- a/diigo-cache/tests/caches.test.ts
+++ b/diigo-cache/tests/caches.test.ts
@@ -159,6 +159,30 @@ describe("page numbering (schema v2)", () => {
 	});
 });
 
+describe("invalidateRecent", () => {
+	it("drops the pages holding anything updated in the last N days, and only those", async () => {
+		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());
+		// deep_dee: one bookmark a day, newest first; page 1 = days 0–99,
+		// page 2 = days 100–199, page 3 = days 200–299
+		await stub.setup({ webappId: "fake-deep-webapp" });
+		for (const n of [1, 2, 3]) await stub.page(n, PAGE_SIZE);
+		expect(await stub.invalidateRecent(150)).toEqual({ pages: 2 });
+		expect((await stub.page(3, PAGE_SIZE)).cached).toBe(true);
+		expect((await stub.page(2, PAGE_SIZE)).cached).toBe(false);
+		expect((await stub.page(1, PAGE_SIZE)).cached).toBe(false);
+	});
+
+	it("drops nothing when nothing cached is that recent, and refuses a bad day count", async () => {
+		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());
+		await stub.setup({ webappId: WEBAPP_ID }); // the plain account's dates are in 2023
+		await stub.page(1, PAGE_SIZE);
+		expect(await stub.invalidateRecent(7)).toEqual({ pages: 0 });
+		expect((await stub.page(1, PAGE_SIZE)).cached).toBe(true);
+		const refused = await stub.invalidateRecent(0).then(() => "", (e: unknown) => String(e));
+		expect(refused).toMatch(/days/);
+	});
+});
+
 describe("eviction", () => {
 	it("a cache miss leaves no undisposed RPC stubs to block eviction", async () => {
 		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());
diff --git a/diigo-cache/tests/fill.test.ts b/diigo-cache/tests/fill.test.ts
index aaed183..fc8cd10 100644
--- a/diigo-cache/tests/fill.test.ts
+++ b/diigo-cache/tests/fill.test.ts
@@ -300,6 +300,20 @@ describe("fill via webkey and Cap'n Web (goal 1e)", () => {
 		expect(html).toContain("event.preventDefault()");
 	});
 
+	it("the capability can invalidate recent pages; the page offers it for each cache", async () => {
+		const { cacheId } = await wireJson("private");
+		const { api, done } = session();
+		try {
+			expect(await api.cache(cacheId).invalidateRecent(7)).toEqual({ pages: 0 });
+		} finally {
+			done();
+		}
+		const html = await (await call("/cache/")).text();
+		expect(html).toContain('id="private-days"');
+		expect(html).toContain('data-action="invalidate"');
+		expect(html).toContain("invalidateRecent(days)");
+	});
+
 	it("serves capnweb's browser build itself (no third-party script beside the key)", async () => {
 		const res = await call("/_capnweb.js");
 		expect(res.headers.get("content-type")).toMatch(/javascript/);